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Commit Graph

33519 Commits

Author SHA1 Message Date
Kees Cook
fb13cb8a04 printk: Introduce kmsg_dump_reason_str()
The pstore subsystem already had a private version of this function.
With the coming addition of the pstore/zone driver, this needs to be
shared. As it really should live with printk, move it there instead.

Link: https://lore.kernel.org/lkml/20200515184434.8470-4-keescook@chromium.org/
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-30 10:34:03 -07:00
Pavel Tatashin
b1f6f161b2 printk: honor the max_reason field in kmsg_dumper
kmsg_dump() allows to dump kmesg buffer for various system events: oops,
panic, reboot, etc. It provides an interface to register a callback
call for clients, and in that callback interface there is a field
"max_reason", but it was getting ignored when set to any "reason"
higher than KMSG_DUMP_OOPS unless "always_kmsg_dump" was passed as
kernel parameter.

Allow clients to actually control their "max_reason", and keep the
current behavior when "max_reason" is not set.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/lkml/20200515184434.8470-3-keescook@chromium.org/
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-30 10:34:03 -07:00
Kees Cook
6d3cf962dd printk: Collapse shutdown types into a single dump reason
To turn the KMSG_DUMP_* reasons into a more ordered list, collapse
the redundant KMSG_DUMP_(RESTART|HALT|POWEROFF) reasons into
KMSG_DUMP_SHUTDOWN. The current users already don't meaningfully
distinguish between them, so there's no need to, as discussed here:
https://lore.kernel.org/lkml/CA+CK2bAPv5u1ih5y9t5FUnTyximtFCtDYXJCpuyjOyHNOkRdqw@mail.gmail.com/

Link: https://lore.kernel.org/lkml/20200515184434.8470-2-keescook@chromium.org/
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-30 10:34:03 -07:00
Thomas Gleixner
76fe06c1e6 irqchip updates for Linux 5.8:
- A few new drivers for the Loongson MIPS platform (HTVEC, PIC, MSI)
 - A cleanup of the __irq_domain_add() API
 - A cleanup of the IRQ simulator to actually use some of
   the irq infrastructure
 - Some fixes for the Sifive PLIC when used in a multi-controller
   context
 - Fixes for the GICv3 ITS to spread interrupts according to the
   load of each CPU, and to honor managed interrupts
 - Numerous cleanups and documentation fixes
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Merge tag 'irqchip-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Pull irqchip updates from Marc Zyngier:

 - A few new drivers for the Loongson MIPS platform (HTVEC, PIC, MSI)
 - A cleanup of the __irq_domain_add() API
 - A cleanup of the IRQ simulator to actually use some of
   the irq infrastructure
 - Some fixes for the Sifive PLIC when used in a multi-controller
   context
 - Fixes for the GICv3 ITS to spread interrupts according to the
   load of each CPU, and to honor managed interrupts
 - Numerous cleanups and documentation fixes
2020-05-30 09:40:12 +02:00
David S. Miller
f9e0ce3ddc Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:

====================
pull-request: bpf 2020-05-29

The following pull-request contains BPF updates for your *net* tree.

We've added 6 non-merge commits during the last 7 day(s) which contain
a total of 4 files changed, 55 insertions(+), 34 deletions(-).

The main changes are:

1) minor verifier fix for fmod_ret progs, from Alexei.

2) af_xdp overflow check, from Bjorn.

3) minor verifier fix for 32bit assignment, from John.

4) powerpc has non-overlapping addr space, from Petr.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-29 15:59:08 -07:00
John Fastabend
3a71dc366d bpf: Fix a verifier issue when assigning 32bit reg states to 64bit ones
With the latest trunk llvm (llvm 11), I hit a verifier issue for
test_prog subtest test_verif_scale1.

The following simplified example illustrate the issue:
    w9 = 0  /* R9_w=inv0 */
    r8 = *(u32 *)(r1 + 80)  /* __sk_buff->data_end */
    r7 = *(u32 *)(r1 + 76)  /* __sk_buff->data */
    ......
    w2 = w9 /* R2_w=inv0 */
    r6 = r7 /* R6_w=pkt(id=0,off=0,r=0,imm=0) */
    r6 += r2 /* R6_w=inv(id=0) */
    r3 = r6 /* R3_w=inv(id=0) */
    r3 += 14 /* R3_w=inv(id=0) */
    if r3 > r8 goto end
    r5 = *(u32 *)(r6 + 0) /* R6_w=inv(id=0) */
       <== error here: R6 invalid mem access 'inv'
    ...
  end:

In real test_verif_scale1 code, "w9 = 0" and "w2 = w9" are in
different basic blocks.

In the above, after "r6 += r2", r6 becomes a scalar, which eventually
caused the memory access error. The correct register state should be
a pkt pointer.

The inprecise register state starts at "w2 = w9".
The 32bit register w9 is 0, in __reg_assign_32_into_64(),
the 64bit reg->smax_value is assigned to be U32_MAX.
The 64bit reg->smin_value is 0 and the 64bit register
itself remains constant based on reg->var_off.

In adjust_ptr_min_max_vals(), the verifier checks for a known constant,
smin_val must be equal to smax_val. Since they are not equal,
the verifier decides r6 is a unknown scalar, which caused later failure.

The llvm10 does not have this issue as it generates different code:
    w9 = 0  /* R9_w=inv0 */
    r8 = *(u32 *)(r1 + 80)  /* __sk_buff->data_end */
    r7 = *(u32 *)(r1 + 76)  /* __sk_buff->data */
    ......
    r6 = r7 /* R6_w=pkt(id=0,off=0,r=0,imm=0) */
    r6 += r9 /* R6_w=pkt(id=0,off=0,r=0,imm=0) */
    r3 = r6 /* R3_w=pkt(id=0,off=0,r=0,imm=0) */
    r3 += 14 /* R3_w=pkt(id=0,off=14,r=0,imm=0) */
    if r3 > r8 goto end
    ...

To fix the above issue, we can include zero in the test condition for
assigning the s32_max_value and s32_min_value to their 64-bit equivalents
smax_value and smin_value.

Further, fix the condition to avoid doing zero extension bounds checks
when s32_min_value <= 0. This could allow for the case where bounds
32-bit bounds (-1,1) get incorrectly translated to (0,1) 64-bit bounds.
When in-fact the -1 min value needs to force U32_MAX bound.

Fixes: 3f50f132d8 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/159077331983.6014.5758956193749002737.stgit@john-Precision-5820-Tower
2020-05-29 13:34:06 -07:00
Alexei Starovoitov
18644cec71 bpf: Fix use-after-free in fmod_ret check
Fix the following issue:
[  436.749342] BUG: KASAN: use-after-free in bpf_trampoline_put+0x39/0x2a0
[  436.749995] Write of size 4 at addr ffff8881ef38b8a0 by task kworker/3:5/2243
[  436.750712]
[  436.752677] Workqueue: events bpf_prog_free_deferred
[  436.753183] Call Trace:
[  436.756483]  bpf_trampoline_put+0x39/0x2a0
[  436.756904]  bpf_prog_free_deferred+0x16d/0x3d0
[  436.757377]  process_one_work+0x94a/0x15b0
[  436.761969]
[  436.762130] Allocated by task 2529:
[  436.763323]  bpf_trampoline_lookup+0x136/0x540
[  436.763776]  bpf_check+0x2872/0xa0a8
[  436.764144]  bpf_prog_load+0xb6f/0x1350
[  436.764539]  __do_sys_bpf+0x16d7/0x3720
[  436.765825]
[  436.765988] Freed by task 2529:
[  436.767084]  kfree+0xc6/0x280
[  436.767397]  bpf_trampoline_put+0x1fd/0x2a0
[  436.767826]  bpf_check+0x6832/0xa0a8
[  436.768197]  bpf_prog_load+0xb6f/0x1350
[  436.768594]  __do_sys_bpf+0x16d7/0x3720

prog->aux->trampoline = tr should be set only when prog is valid.
Otherwise prog freeing will try to put trampoline via prog->aux->trampoline,
but it may not point to a valid trampoline.

Fixes: 6ba43b761c ("bpf: Attachment verification for BPF_MODIFY_RETURN")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20200529043839.15824-2-alexei.starovoitov@gmail.com
2020-05-29 22:25:58 +02:00
Lai Jiangshan
b8f06b0444 workqueue: remove useless unlock() and lock() in series
This is no point to unlock() and then lock() the same mutex
back to back.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-29 10:25:23 -04:00
Lai Jiangshan
4f3f4cf388 workqueue: void unneeded requeuing the pwq in rescuer thread
008847f66c ("workqueue: allow rescuer thread to do more work.") made
the rescuer worker requeue the pwq immediately if there may be more
work items which need rescuing instead of waiting for the next mayday
timer expiration.  Unfortunately, it checks only whether the pool needs
help from rescuers, but it doesn't check whether the pwq has work items
in the pool (the real reason that this rescuer can help for the pool).

The patch adds the check and void unneeded requeuing.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-29 10:22:10 -04:00
Sebastian Andrzej Siewior
a9b8a98529 workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t
The workqueue code has it's internal spinlocks (pool::lock), which
are acquired on most workqueue operations. These spinlocks are
converted to 'sleeping' spinlocks on a RT-kernel.

Workqueue functions can be invoked from contexts which are truly atomic
even on a PREEMPT_RT enabled kernel. Taking sleeping locks from such
contexts is forbidden.

The pool::lock hold times are bound and the code sections are
relatively short, which allows to convert pool::lock and as a
consequence wq_mayday_lock to raw spinlocks which are truly spinning
locks even on a PREEMPT_RT kernel.

With the previous conversion of the manager waitqueue to a simple
waitqueue workqueues are now fully RT compliant.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-29 10:03:47 -04:00
Sebastian Andrzej Siewior
d8bb65ab70 workqueue: Use rcuwait for wq_manager_wait
The workqueue code has it's internal spinlock (pool::lock) and also
implicit spinlock usage in the wq_manager waitqueue. These spinlocks
are converted to 'sleeping' spinlocks on a RT-kernel.

Workqueue functions can be invoked from contexts which are truly atomic
even on a PREEMPT_RT enabled kernel. Taking sleeping locks from such
contexts is forbidden.

pool::lock can be converted to a raw spinlock as the lock held times
are short. But the workqueue manager waitqueue is handled inside of
pool::lock held regions which again violates the lock nesting rules
of raw and regular spinlocks.

The manager waitqueue has no special requirements like custom wakeup
callbacks or mass wakeups. While it does not use exclusive wait mode
explicitly there is no strict requirement to queue the waiters in a
particular order as there is only one waiter at a time.

This allows to replace the waitqueue with rcuwait which solves the
locking problem because rcuwait relies on existing locking.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-29 10:00:35 -04:00
Boris Burkov
936f2a70f2 cgroup: add cpu.stat file to root cgroup
Currently, the root cgroup does not have a cpu.stat file. Add one which
is consistent with /proc/stat to capture global cpu statistics that
might not fall under cgroup accounting.

We haven't done this in the past because the data are already presented
in /proc/stat and we didn't want to add overhead from collecting root
cgroup stats when cgroups are configured, but no cgroups have been
created.

By keeping the data consistent with /proc/stat, I think we avoid the
first problem, while improving the usability of cgroups stats.
We avoid the second problem by computing the contents of cpu.stat from
existing data collected for /proc/stat anyway.

Signed-off-by: Boris Burkov <boris@bur.io>
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-28 10:06:35 -04:00
Marek Vasut
1d0326f352 genirq: Check irq_data_get_irq_chip() return value before use
irq_data_get_irq_chip() can return NULL, however it is expected that this
never happens. If a buggy driver leads to NULL being returned from
irq_data_get_irq_chip(), warn about it instead of crashing the machine.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

To: linux-arm-kernel@lists.infradead.org
2020-05-28 15:58:04 +02:00
Ingo Molnar
1f8db41505 sched/headers: Split out open-coded prototypes into kernel/sched/smp.h
Move the prototypes for sched_ttwu_pending() and send_call_function_single_ipi()
into the newly created kernel/sched/smp.h header, to make sure they are all
the same, and to architectures happy that use -Wmissing-prototypes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-28 11:03:20 +02:00
Peter Zijlstra
a148866489 sched: Replace rq::wake_list
The recent commit: 90b5363acd ("sched: Clean up scheduler_ipi()")
got smp_call_function_single_async() subtly wrong. Even though it will
return -EBUSY when trying to re-use a csd, that condition is not
atomic and still requires external serialization.

The change in ttwu_queue_remote() got this wrong.

While on first reading ttwu_queue_remote() has an atomic test-and-set
that appears to serialize the use, the matching 'release' is not in
the right place to actually guarantee this serialization.

The actual race is vs the sched_ttwu_pending() call in the idle loop;
that can run the wakeup-list without consuming the CSD.

Instead of trying to chain the lists, merge them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161908.129371594@infradead.org
2020-05-28 10:54:16 +02:00
Peter Zijlstra
126c2092e5 sched: Add rq::ttwu_pending
In preparation of removing rq->wake_list, replace the
!list_empty(rq->wake_list) with rq->ttwu_pending. This is not fully
equivalent as this new variable is racy.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161908.070399698@infradead.org
2020-05-28 10:54:16 +02:00
Peter Zijlstra
4b44a21dd6 irq_work, smp: Allow irq_work on call_single_queue
Currently irq_work_queue_on() will issue an unconditional
arch_send_call_function_single_ipi() and has the handler do
irq_work_run().

This is unfortunate in that it makes the IPI handler look at a second
cacheline and it misses the opportunity to avoid the IPI. Instead note
that struct irq_work and struct __call_single_data are very similar in
layout, so use a few bits in the flags word to encode a type and stick
the irq_work on the call_single_queue list.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161908.011635912@infradead.org
2020-05-28 10:54:15 +02:00
Peter Zijlstra
b2a02fc43a smp: Optimize send_call_function_single_ipi()
Just like the ttwu_queue_remote() IPI, make use of _TIF_POLLING_NRFLAG
to avoid sending IPIs to idle CPUs.

[ mingo: Fix UP build bug. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161907.953304789@infradead.org
2020-05-28 10:54:15 +02:00
Peter Zijlstra
afaa653c56 smp: Move irq_work_run() out of flush_smp_call_function_queue()
This ensures flush_smp_call_function_queue() is strictly about
call_single_queue.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161907.895109676@infradead.org
2020-05-28 10:54:15 +02:00
Peter Zijlstra
52103be07d smp: Optimize flush_smp_call_function_queue()
The call_single_queue can contain (two) different callbacks,
synchronous and asynchronous. The current interrupt handler runs them
in-order, which means that remote CPUs that are waiting for their
synchronous call can be delayed by running asynchronous callbacks.

Rework the interrupt handler to first run the synchonous callbacks.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161907.836818381@infradead.org
2020-05-28 10:54:15 +02:00
Peter Zijlstra
19a1f5ec69 sched: Fix smp_call_function_single_async() usage for ILB
The recent commit: 90b5363acd ("sched: Clean up scheduler_ipi()")
got smp_call_function_single_async() subtly wrong. Even though it will
return -EBUSY when trying to re-use a csd, that condition is not
atomic and still requires external serialization.

The change in kick_ilb() got this wrong.

While on first reading kick_ilb() has an atomic test-and-set that
appears to serialize the use, the matching 'release' is not in the
right place to actually guarantee this serialization.

Rework the nohz_idle_balance() trigger so that the release is in the
IPI callback and thus guarantees the required serialization for the
CSD.

Fixes: 90b5363acd ("sched: Clean up scheduler_ipi()")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: mgorman@techsingularity.net
Link: https://lore.kernel.org/r/20200526161907.778543557@infradead.org
2020-05-28 10:54:15 +02:00
Ingo Molnar
58ef57b16d Merge branch 'core/rcu' into sched/core, to pick up dependency
We are going to rely on the loosening of RCU callback semantics,
introduced by this commit:

  806f04e9fd: ("rcu: Allow for smp_call_function() running callbacks from idle")

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-28 10:52:53 +02:00
Ingo Molnar
498bdcdb94 Merge branch 'sched/urgent' into sched/core, to pick up fix
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-28 10:52:37 +02:00
Peter Zijlstra
806f04e9fd rcu: Allow for smp_call_function() running callbacks from idle
Current RCU hard relies on smp_call_function() callbacks running from
interrupt context. A pending optimization is going to break that, it
will allow idle CPUs to run the callbacks from the idle loop. This
avoids raising the IPI on the requesting CPU and avoids handling an
exception on the receiving CPU.

Change rcu_is_cpu_rrupt_from_idle() to also accept task context,
provided it is the idle task.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lore.kernel.org/r/20200527171236.GC706495@hirez.programming.kicks-ass.net
2020-05-28 10:50:12 +02:00
Ingo Molnar
4f470fff67 Linux 5.7-rc7
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Merge tag 'v5.7-rc7' into WIP.locking/core, to refresh the tree

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-28 10:30:40 +02:00
Ingo Molnar
0bffedbce9 Linux 5.7-rc7
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Merge tag 'v5.7-rc7' into perf/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-05-28 07:58:12 +02:00
Linus Torvalds
3301f6ae2d Merge branch 'for-5.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:

 - Reverted stricter synchronization for cgroup recursive stats which
   was prepping it for event counter usage which never got merged. The
   change was causing performation regressions in some cases.

 - Restore bpf-based device-cgroup operation even when cgroup1 device
   cgroup is disabled.

 - An out-param init fix.

* 'for-5.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  device_cgroup: Cleanup cgroup eBPF device filter code
  xattr: fix uninitialized out-param
  Revert "cgroup: Add memory barriers to plug cgroup_rstat_updated() race window"
2020-05-27 10:58:19 -07:00
Domenico Andreoli
ad1e4f74c0 PM: hibernate: Restrict writes to the resume device
Hibernation via snapshot device requires write permission to the swap
block device, the one that more often (but not necessarily) is used to
store the hibernation image.

With this patch, such permissions are granted iff:

 1) snapshot device config option is enabled
 2) swap partition is used as resume device

In other circumstances the swap device is not writable from userspace.

In order to achieve this, every write attempt to a swap device is
checked against the device configured as part of the uswsusp API [0]
using a pointer to the inode struct in memory. If the swap device being
written was not configured for resuming, the write request is denied.

NOTE: this implementation works only for swap block devices, where the
inode configured by swapon (which sets S_SWAPFILE) is the same used
by SNAPSHOT_SET_SWAP_AREA.

In case of swap file, SNAPSHOT_SET_SWAP_AREA indeed receives the inode
of the block device containing the filesystem where the swap file is
located (+ offset in it) which is never passed to swapon and then has
not set S_SWAPFILE.

As result, the swap file itself (as a file) has never an option to be
written from userspace. Instead it remains writable if accessed directly
from the containing block device, which is always writeable from root.

[0] Documentation/power/userland-swsusp.rst

v2:
 - rename is_hibernate_snapshot_dev() to is_hibernate_resume_dev()
 - fix description so to correctly refer to the resume device

Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Acked-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-27 17:55:59 +02:00
Zhang Qiang
342ed2400b workqueue: Remove unnecessary kfree() call in rcu_free_wq()
The data structure member "wq->rescuer" was reset to a null pointer
in one if branch. It was passed to a call of the function "kfree"
in the callback function "rcu_free_wq" (which was eventually executed).
The function "kfree" does not perform more meaningful data processing
for a passed null pointer (besides immediately returning from such a call).
Thus delete this function call which became unnecessary with the referenced
software update.

Fixes: def98c84b6 ("workqueue: Fix spurious sanity check failures in destroy_workqueue()")

Suggested-by: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Zhang Qiang <qiang.zhang@windriver.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-27 09:52:41 -04:00
Dan Williams
3234ac664a /dev/mem: Revoke mappings when a driver claims the region
Close the hole of holding a mapping over kernel driver takeover event of
a given address range.

Commit 90a545e981 ("restrict /dev/mem to idle io memory ranges")
introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the
kernel against scenarios where a /dev/mem user tramples memory that a
kernel driver owns. However, this protection only prevents *new* read(),
write() and mmap() requests. Established mappings prior to the driver
calling request_mem_region() are left alone.

Especially with persistent memory, and the core kernel metadata that is
stored there, there are plentiful scenarios for a /dev/mem user to
violate the expectations of the driver and cause amplified damage.

Teach request_mem_region() to find and shoot down active /dev/mem
mappings that it believes it has successfully claimed for the exclusive
use of the driver. Effectively a driver call to request_mem_region()
becomes a hole-punch on the /dev/mem device.

The typical usage of unmap_mapping_range() is part of
truncate_pagecache() to punch a hole in a file, but in this case the
implementation is only doing the "first half" of a hole punch. Namely it
is just evacuating current established mappings of the "hole", and it
relies on the fact that /dev/mem establishes mappings in terms of
absolute physical address offsets. Once existing mmap users are
invalidated they can attempt to re-establish the mapping, or attempt to
continue issuing read(2) / write(2) to the invalidated extent, but they
will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can
block those subsequent accesses.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 90a545e981 ("restrict /dev/mem to idle io memory ranges")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-27 11:10:05 +02:00
Zefan Li
6b6ebb3474 cgroup: Remove stale comments
- The default root is where we can create v2 cgroups.
- The __DEVEL__sane_behavior mount option has been removed long long ago.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-26 13:20:24 -04:00
Thomas Gleixner
07325d4a90 rcu: Provide rcu_irq_exit_check_preempt()
Provide a debug check which can be invoked from exception return to kernel
mode before an attempt is made to schedule. Warn if RCU is not ready for
this.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20200521202117.089709607@linutronix.de
2020-05-26 19:05:11 +02:00
Paul E. McKenney
aaf2bc50df rcu: Abstract out rcu_irq_enter_check_tick() from rcu_nmi_enter()
There will likely be exception handlers that can sleep, which rules
out the usual approach of invoking rcu_nmi_enter() on entry and also
rcu_nmi_exit() on all exit paths.  However, the alternative approach of
just not calling anything can prevent RCU from coaxing quiescent states
from nohz_full CPUs that are looping in the kernel:  RCU must instead
IPI them explicitly.  It would be better to enable the scheduler tick
on such CPUs to interact with RCU in a lighter-weight manner, and this
enabling is one of the things that rcu_nmi_enter() currently does.

What is needed is something that helps RCU coax quiescent states while
not preventing subsequent sleeps.  This commit therefore splits out the
nohz_full scheduler-tick enabling from the rest of the rcu_nmi_enter()
logic into a new function named rcu_irq_enter_check_tick().

[ tglx: Renamed the function and made it a nop when context tracking is off ]
[ mingo: Fixed a CONFIG_NO_HZ_FULL assumption, harmonized and fixed all the
         comment blocks and cleaned up rcu_nmi_enter()/exit() definitions. ]

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200521202116.996113173@linutronix.de
2020-05-26 19:04:18 +02:00
Jens Axboe
18f855e574 sched/fair: Don't NUMA balance for kthreads
Stefano reported a crash with using SQPOLL with io_uring:

  BUG: kernel NULL pointer dereference, address: 00000000000003b0
  CPU: 2 PID: 1307 Comm: io_uring-sq Not tainted 5.7.0-rc7 #11
  RIP: 0010:task_numa_work+0x4f/0x2c0
  Call Trace:
   task_work_run+0x68/0xa0
   io_sq_thread+0x252/0x3d0
   kthread+0xf9/0x130
   ret_from_fork+0x35/0x40

which is task_numa_work() oopsing on current->mm being NULL.

The task work is queued by task_tick_numa(), which checks if current->mm is
NULL at the time of the call. But this state isn't necessarily persistent,
if the kthread is using use_mm() to temporarily adopt the mm of a task.

Change the task_tick_numa() check to exclude kernel threads in general,
as it doesn't make sense to attempt ot balance for kthreads anyway.

Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/865de121-8190-5d30-ece5-3b097dc74431@kernel.dk
2020-05-26 18:34:58 +02:00
Arnd Bergmann
502afe7f04 Qualcomm driver updates for v5.8
This contains a large set of cleanups, bug fixes, general improvements
 and documentation fixes for the RPMH driver. It adds a debugfs mechanism
 for inspecting Command DB. Socinfo got the "soc_id" attribute defines
 and definitions for a various variants of MSM8939.
 
 RPMH, RPMPD and RPMHPD where made possible to build as modules, but RPMH
 had to be reverted due to a compilation issue when tracing is enabled.
 
 RPMHPD gained power-domains for the SM8250 voltage corners.
 
 The SCM driver gained fixes for two build warnings and the SMP2P had an
 unnecessary error print removed.
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Merge tag 'qcom-drivers-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux into arm/drivers

Qualcomm driver updates for v5.8

This contains a large set of cleanups, bug fixes, general improvements
and documentation fixes for the RPMH driver. It adds a debugfs mechanism
for inspecting Command DB. Socinfo got the "soc_id" attribute defines
and definitions for a various variants of MSM8939.

RPMH, RPMPD and RPMHPD where made possible to build as modules, but RPMH
had to be reverted due to a compilation issue when tracing is enabled.

RPMHPD gained power-domains for the SM8250 voltage corners.

The SCM driver gained fixes for two build warnings and the SMP2P had an
unnecessary error print removed.

* tag 'qcom-drivers-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux: (42 commits)
  Revert "soc: qcom: rpmh: Allow RPMH driver to be loaded as a module"
  soc: qcom: rpmh-rsc: Remove the pm_lock
  soc: qcom: rpmh-rsc: Simplify locking by eliminating the per-TCS lock
  kernel/cpu_pm: Fix uninitted local in cpu_pm
  soc: qcom: rpmh-rsc: We aren't notified of our own failure w/ NOTIFY_BAD
  soc: qcom: rpmh-rsc: Correctly ignore CPU_CLUSTER_PM notifications
  firmware: qcom_scm-legacy: Replace zero-length array with flexible-array
  soc: qcom: rpmh-rsc: Timeout after 1 second in write_tcs_reg_sync()
  soc: qcom: rpmh-rsc: Factor "tcs_reg_addr" and "tcs_cmd_addr" calculation
  soc: qcom: socinfo: add msm8936/39 and apq8036/39 soc ids
  soc: qcom: aoss: Add SM8250 compatible
  soc: qcom: pdr: Remove impossible error condition
  soc: qcom: rpmh: Dirt can only make you dirtier, not cleaner
  soc: qcom: rpmhpd: Add SM8250 power domains
  firmware: qcom_scm: fix bogous abuse of dma-direct internals
  dt-bindings: soc: qcom: apr: Use generic node names for APR services
  firmware: qcom_scm: Remove unneeded conversion to bool
  soc: qcom: cmd-db: Properly endian swap the slv_id for debugfs
  soc: qcom: cmd-db: Use 5 digits for printing address
  soc: qcom: cmd-db: Cast sizeof() to int to silence field width warning
  ...

Link: https://lore.kernel.org/r/20200519052533.1250024-1-bjorn.andersson@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2020-05-25 23:19:06 +02:00
Greg Kroah-Hartman
344235f557 Merge 5.7-rc7 into tty-next
We need the tty/serial fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-25 13:22:05 +02:00
Mel Gorman
2ebb177175 sched/core: Offload wakee task activation if it the wakee is descheduling
The previous commit:

  c6e7bd7afa: ("sched/core: Optimize ttwu() spinning on p->on_cpu")

avoids spinning on p->on_rq when the task is descheduling, but only if the
wakee is on a CPU that does not share cache with the waker.

This patch offloads the activation of the wakee to the CPU that is about to
go idle if the task is the only one on the runqueue. This potentially allows
the waker task to continue making progress when the wakeup is not strictly
synchronous.

This is very obvious with netperf UDP_STREAM running on localhost. The
waker is sending packets as quickly as possible without waiting for any
reply. It frequently wakes the server for the processing of packets and
when netserver is using local memory, it quickly completes the processing
and goes back to idle. The waker often observes that netserver is on_rq
and spins excessively leading to a drop in throughput.

This is a comparison of 5.7-rc6 against "sched: Optimize ttwu() spinning
on p->on_cpu" and against this patch labeled vanilla, optttwu-v1r1 and
localwakelist-v1r2 respectively.

                                  5.7.0-rc6              5.7.0-rc6              5.7.0-rc6
                                    vanilla           optttwu-v1r1     localwakelist-v1r2
Hmean     send-64         251.49 (   0.00%)      258.05 *   2.61%*      305.59 *  21.51%*
Hmean     send-128        497.86 (   0.00%)      519.89 *   4.43%*      600.25 *  20.57%*
Hmean     send-256        944.90 (   0.00%)      997.45 *   5.56%*     1140.19 *  20.67%*
Hmean     send-1024      3779.03 (   0.00%)     3859.18 *   2.12%*     4518.19 *  19.56%*
Hmean     send-2048      7030.81 (   0.00%)     7315.99 *   4.06%*     8683.01 *  23.50%*
Hmean     send-3312     10847.44 (   0.00%)    11149.43 *   2.78%*    12896.71 *  18.89%*
Hmean     send-4096     13436.19 (   0.00%)    13614.09 (   1.32%)    15041.09 *  11.94%*
Hmean     send-8192     22624.49 (   0.00%)    23265.32 *   2.83%*    24534.96 *   8.44%*
Hmean     send-16384    34441.87 (   0.00%)    36457.15 *   5.85%*    35986.21 *   4.48%*

Note that this benefit is not universal to all wakeups, it only applies
to the case where the waker often spins on p->on_rq.

The impact can be seen from a "perf sched latency" report generated from
a single iteration of one packet size:

   -----------------------------------------------------------------------------------------------------------------
    Task                  |   Runtime ms  | Switches | Average delay ms | Maximum delay ms | Maximum delay at       |
   -----------------------------------------------------------------------------------------------------------------

  vanilla
    netperf:4337          |  21709.193 ms |     2932 | avg:    0.002 ms | max:    0.041 ms | max at:    112.154512 s
    netserver:4338        |  14629.459 ms |  5146990 | avg:    0.001 ms | max: 1615.864 ms | max at:    140.134496 s

  localwakelist-v1r2
    netperf:4339          |  29789.717 ms |     2460 | avg:    0.002 ms | max:    0.059 ms | max at:    138.205389 s
    netserver:4340        |  18858.767 ms |  7279005 | avg:    0.001 ms | max:    0.362 ms | max at:    135.709683 s
   -----------------------------------------------------------------------------------------------------------------

Note that the average wakeup delay is quite small on both the vanilla
kernel and with the two patches applied. However, there are significant
outliers with the vanilla kernel with the maximum one measured as 1615
milliseconds with a vanilla kernel but never worse than 0.362 ms with
both patches applied and a much higher rate of context switching.

Similarly a separate profile of cycles showed that 2.83% of all cycles
were spent in try_to_wake_up() with almost half of the cycles spent
on spinning on p->on_rq. With the two patches, the percentage of cycles
spent in try_to_wake_up() drops to 1.13%

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: valentin.schneider@arm.com
Cc: Hillf Danton <hdanton@sina.com>
Cc: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/r/20200524202956.27665-3-mgorman@techsingularity.net
2020-05-25 07:04:10 +02:00
Peter Zijlstra
c6e7bd7afa sched/core: Optimize ttwu() spinning on p->on_cpu
Both Rik and Mel reported seeing ttwu() spend significant time on:

  smp_cond_load_acquire(&p->on_cpu, !VAL);

Attempt to avoid this by queueing the wakeup on the CPU that owns the
p->on_cpu value. This will then allow the ttwu() to complete without
further waiting.

Since we run schedule() with interrupts disabled, the IPI is
guaranteed to happen after p->on_cpu is cleared, this is what makes it
safe to queue early.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: valentin.schneider@arm.com
Cc: Hillf Danton <hdanton@sina.com>
Cc: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/r/20200524202956.27665-2-mgorman@techsingularity.net
2020-05-25 07:01:44 +02:00
David S. Miller
13209a8f73 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
The MSCC bug fix in 'net' had to be slightly adjusted because the
register accesses are done slightly differently in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-24 13:47:27 -07:00
Linus Torvalds
9e61d12bac A set of fixes for the scheduler:
- Fix handling of throttled parents in enqueue_task_fair() completely. The
    recent fix overlooked a corner case where the first iteration terminates
    do a entiry being on rq which makes the list management incomplete and
    later triggers the assertion which checks for completeness.
 
  - Fix a similar problem in unthrottle_cfs_rq().
 
  - Show the correct uclamp values in procfs which prints the effective
    value twice instead of requested and effective.
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Merge tag 'sched-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Thomas Gleixner:
 "A set of fixes for the scheduler:

   - Fix handling of throttled parents in enqueue_task_fair() completely.

     The recent fix overlooked a corner case where the first iteration
     terminates due to an entity already being on the runqueue which
     makes the list management incomplete and later triggers the
     assertion which checks for completeness.

   - Fix a similar problem in unthrottle_cfs_rq().

   - Show the correct uclamp values in procfs which prints the effective
     value twice instead of requested and effective"

* tag 'sched-urgent-2020-05-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list
  sched/debug: Fix requested task uclamp values shown in procfs
  sched/fair: Fix enqueue_task_fair() warning some more
2020-05-24 10:14:58 -07:00
Shreyas Joshi
48021f9813 printk: handle blank console arguments passed in.
If uboot passes a blank string to console_setup then it results in
a trashed memory. Ultimately, the kernel crashes during freeing up
the memory.

This fix checks if there is a blank parameter being
passed to console_setup from uboot. In case it detects that
the console parameter is blank then it doesn't setup the serial
device and it gracefully exits.

Link: https://lore.kernel.org/r/20200522065306.83-1-shreyas.joshi@biamp.com
Signed-off-by: Shreyas Joshi <shreyas.joshi@biamp.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Better format the commit message and code, remove unnecessary brackets.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
2020-05-22 10:34:34 +02:00
John Fastabend
cac616db39 bpf: Verifier track null pointer branch_taken with JNE and JEQ
Currently, when considering the branches that may be taken for a jump
instruction if the register being compared is a pointer the verifier
assumes both branches may be taken. But, if the jump instruction
is comparing if a pointer is NULL we have this information in the
verifier encoded in the reg->type so we can do better in these cases.
Specifically, these two common cases can be handled.

 * If the instruction is BPF_JEQ and we are comparing against a
   zero value. This test is 'if ptr == 0 goto +X' then using the
   type information in reg->type we can decide if the ptr is not
   null. This allows us to avoid pushing both branches onto the
   stack and instead only use the != 0 case. For example
   PTR_TO_SOCK and PTR_TO_SOCK_OR_NULL encode the null pointer.
   Note if the type is PTR_TO_SOCK_OR_NULL we can not learn anything.
   And also if the value is non-zero we learn nothing because it
   could be any arbitrary value a different pointer for example

 * If the instruction is BPF_JNE and ware comparing against a zero
   value then a similar analysis as above can be done. The test in
   asm looks like 'if ptr != 0 goto +X'. Again using the type
   information if the non null type is set (from above PTR_TO_SOCK)
   we know the jump is taken.

In this patch we extend is_branch_taken() to consider this extra
information and to return only the branch that will be taken. This
resolves a verifier issue reported with C code like the following.
See progs/test_sk_lookup_kern.c in selftests.

 sk = bpf_sk_lookup_tcp(skb, tuple, tuple_len, BPF_F_CURRENT_NETNS, 0);
 bpf_printk("sk=%d\n", sk ? 1 : 0);
 if (sk)
   bpf_sk_release(sk);
 return sk ? TC_ACT_OK : TC_ACT_UNSPEC;

In the above the bpf_printk() will resolve the pointer from
PTR_TO_SOCK_OR_NULL to PTR_TO_SOCK. Then the second test guarding
the release will cause the verifier to walk both paths resulting
in the an unreleased sock reference. See verifier/ref_tracking.c
in selftests for an assembly version of the above.

After the above additional logic is added the C code above passes
as expected.

Reported-by: Andrey Ignatov <rdna@fb.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/159009164651.6313.380418298578070501.stgit@john-Precision-5820-Tower
2020-05-21 17:44:25 -07:00
Björn Töpel
d20a1676df xsk: Move xskmap.c to net/xdp/
The XSKMAP is partly implemented by net/xdp/xsk.c. Move xskmap.c from
kernel/bpf/ to net/xdp/, which is the logical place for AF_XDP related
code. Also, move AF_XDP struct definitions, and function declarations
only used by AF_XDP internals into net/xdp/xsk.h.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200520192103.355233-3-bjorn.topel@gmail.com
2020-05-21 17:31:26 -07:00
J. Bruce Fields
6670ee2ef2 Merge branch 'nfsd-5.8' of git://linux-nfs.org/~cel/cel-2.6 into for-5.8-incoming
Highlights of this series:
* Remove serialization of sending RPC/RDMA Replies
* Convert the TCP socket send path to use xdr_buf::bvecs (pre-requisite for
RPC-on-TLS)
* Fix svcrdma backchannel sendto return code
* Convert a number of dprintk call sites to use tracepoints
* Fix the "suggest braces around empty body in an 'else' statement" warning
2020-05-21 10:58:15 -04:00
Bruno Meneguele
8ece3b3eb5 kernel/printk: add kmsg SEEK_CUR handling
Userspace libraries, e.g. glibc's dprintf(), perform a SEEK_CUR operation
over any file descriptor requested to make sure the current position isn't
pointing to junk due to previous manipulation of that same fd. And whenever
that fd doesn't have support for such operation, the userspace code expects
-ESPIPE to be returned.

However, when the fd in question references the /dev/kmsg interface, the
current kernel code state returns -EINVAL instead, causing an unexpected
behavior in userspace: in the case of glibc, when -ESPIPE is returned it
gets ignored and the call completes successfully, while returning -EINVAL
forces dprintf to fail without performing any action over that fd:

  if (_IO_SEEKOFF (fp, (off64_t)0, _IO_seek_cur, _IOS_INPUT|_IOS_OUTPUT) ==
  _IO_pos_BAD && errno != ESPIPE)
    return NULL;

With this patch we make sure to return the correct value when SEEK_CUR is
requested over kmsg and also add some kernel doc information to formalize
this behavior.

Link: https://lore.kernel.org/r/20200317103344.574277-1-bmeneg@redhat.com
Cc: linux-kernel@vger.kernel.org
Cc: rostedt@goodmis.org,
Cc: David.Laight@ACULAB.COM
Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2020-05-21 13:32:25 +02:00
Ethon Paul
325606af57 printk: Fix a typo in comment "interator"->"iterator"
There is a typo in comment, fix it.

Signed-off-by: Ethon Paul <ethp@qq.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2020-05-21 13:31:33 +02:00
Andy Shevchenko
9ed78b05f9 irqdomain: Allow software nodes for IRQ domain creation
In some cases we need to have an IRQ domain created out of software node.

One of such cases is DesignWare GPIO driver when it's instantiated from
half-baked ACPI table (alas, we can't fix it for devices which are few years
on market) and thus using software nodes to quirk this. But the driver
is using IRQ domains based on per GPIO port firmware nodes, which are in
the above case software ones. This brings a warning message to be printed

  [   73.957183] irq: Invalid fwnode type for irqdomain

and creates an anonymous IRQ domain without a debugfs entry.

Allowing software nodes to be valid for IRQ domains rids us of the warning
and debugs gets correctly populated.

  % ls -1 /sys/kernel/debug/irq/domains/
  ...
  intel-quark-dw-apb-gpio:portA

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[maz: refactored commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200520164927.39090-3-andriy.shevchenko@linux.intel.com
2020-05-21 10:53:17 +01:00
Andy Shevchenko
87526603c8 irqdomain: Get rid of special treatment for ACPI in __irq_domain_add()
Now that __irq_domain_add() is able to better deals with generic
fwnodes, there is no need to special-case ACPI anymore.

Get rid of the special treatment for ACPI.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200520164927.39090-2-andriy.shevchenko@linux.intel.com
2020-05-21 10:51:50 +01:00
Andy Shevchenko
181e9d4efa irqdomain: Make __irq_domain_add() less OF-dependent
__irq_domain_add() relies in some places on the fact that the fwnode
can be only of type OF. This prevents refactoring of the code to support
other types of fwnode. Make it less OF-dependent by switching it
to use the fwnode directly where it makes sense.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200520164927.39090-1-andriy.shevchenko@linux.intel.com
2020-05-21 10:50:30 +01:00
Andrii Nakryiko
dfeb376dd4 bpf: Prevent mmap()'ing read-only maps as writable
As discussed in [0], it's dangerous to allow mapping BPF map, that's meant to
be frozen and is read-only on BPF program side, because that allows user-space
to actually store a writable view to the page even after it is frozen. This is
exacerbated by BPF verifier making a strong assumption that contents of such
frozen map will remain unchanged. To prevent this, disallow mapping
BPF_F_RDONLY_PROG mmap()'able BPF maps as writable, ever.

  [0] https://lore.kernel.org/bpf/CAEf4BzYGWYhXdp6BJ7_=9OQPJxQpgug080MMjdSB72i9R+5c6g@mail.gmail.com/

Fixes: fc9702273e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/bpf/20200519053824.1089415-1-andriin@fb.com
2020-05-20 20:21:53 -07:00
Richard Guy Briggs
9d44a121c5 audit: add subj creds to NETFILTER_CFG record to
Some table unregister actions seem to be initiated by the kernel to
garbage collect unused tables that are not initiated by any userspace
actions.  It was found to be necessary to add the subject credentials to
cover this case to reveal the source of these actions.  A sample record:

The uid, auid, tty, ses and exe fields have not been included since they
are in the SYSCALL record and contain nothing useful in the non-user
context.

Here are two sample orphaned records:

  type=NETFILTER_CFG msg=audit(2020-05-20 12:14:36.505:5) : table=filter family=ipv4 entries=0 op=register pid=1 subj=kernel comm=swapper/0

  type=NETFILTER_CFG msg=audit(2020-05-20 12:15:27.701:301) : table=nat family=bridge entries=0 op=unregister pid=30 subj=system_u:system_r:kernel_t:s0 comm=kworker/u4:1

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-20 18:09:19 -04:00
Eric W. Biederman
87b047d2be exec: Teach prepare_exec_creds how exec treats uids & gids
It is almost possible to use the result of prepare_exec_creds with no
modifications during exec.  Update prepare_exec_creds to initialize
the suid and the fsuid to the euid, and the sgid and the fsgid to the
egid.  This is all that is needed to handle the common case of exec
when nothing special like a setuid exec is happening.

That this preserves the existing behavior of exec can be verified
by examing bprm_fill_uid and cap_bprm_set_creds.

This change makes it clear that the later parts of exec that
update bprm->cred are just need to handle special cases such
as setuid exec and change of domains.

Link: https://lkml.kernel.org/r/871rng22dm.fsf_-_@x220.int.ebiederm.org
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-20 14:44:21 -05:00
Christoph Hellwig
c928f642c2 fs: rename pipe_buf ->steal to ->try_steal
And replace the arcane return value convention with a simple bool
where true means success and false means failure.

[AV: braino fix folded in]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-20 12:14:10 -04:00
Christoph Hellwig
b8d9e7f241 fs: make the pipe_buf_operations ->confirm operation optional
Just return 0 for success if it is not present.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-20 12:11:26 -04:00
Christoph Hellwig
76887c2567 fs: make the pipe_buf_operations ->steal operation optional
Just return 1 for failure if it is not present.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-20 12:11:26 -04:00
Christoph Hellwig
6797d97ab9 trace: remove tracing_pipe_buf_ops
tracing_pipe_buf_ops has identical ops to default_pipe_buf_ops, so use
that instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-20 12:11:26 -04:00
Michael Ellerman
217ba7dcce Merge branch 'topic/uaccess-ppc' into next
Merge our uaccess-ppc topic branch. It is based on the uaccess topic
branch that we're sharing with Viro.

This includes the addition of user_[read|write]_access_begin(), as
well as some powerpc specific changes to our uaccess routines that
would conflict badly if merged separately.
2020-05-20 23:37:33 +10:00
Paolo Bonzini
9d5272f5e3 Merge tag 'noinstr-x86-kvm-2020-05-16' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into HEAD 2020-05-20 03:40:09 -04:00
Julia Lawall
fc9d276f22 tracing/probe: reverse arguments to list_add
Elsewhere in the file, the function trace_kprobe_has_same_kprobe uses
a trace_probe_event.probes object as the second argument of
list_for_each_entry, ie as a list head, while the list_for_each_entry
iterates over the list fields of the trace_probe structures, making
them the list elements.  So, exchange the arguments on the list_add
call to put the list head in the second argument.

Since both list_head structures were just initialized, this problem
did not cause any loss of information.

Link: https://lkml.kernel.org/r/1588879808-24488-1-git-send-email-Julia.Lawall@inria.fr

Fixes: 60d53e2c3b ("tracing/probe: Split trace_event related data from trace_probe")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-19 21:10:50 -04:00
Cheng Jian
c143b7753b ftrace: show debugging information when panic_on_warn set
When an anomaly is detected in the function call modification
code, ftrace_bug() is called to disable function tracing as well
as give some warn and information that may help debug the problem.

But currently, we call FTRACE_WARN_ON_ONCE() first in ftrace_bug(),
so when panic_on_warn is set, we can't see the debugging information
here. Call FTRACE_WARN_ON_ONCE() at the end of ftrace_bug() to ensure
that the debugging information is displayed first.

after this patch, the dmesg looks like:

	------------[ ftrace bug ]------------
	ftrace failed to modify
	[<ffff800010081004>] bcm2835_handle_irq+0x4/0x58
	 actual:   1f:20:03:d5
	Setting ftrace call site to call ftrace function
	ftrace record flags: 80000001
	 (1)
	 expected tramp: ffff80001009d6f0
	------------[ cut here ]------------
	WARNING: CPU: 2 PID: 1635 at kernel/trace/ftrace.c:2078 ftrace_bug+0x204/0x238
	Kernel panic - not syncing: panic_on_warn set ...
	CPU: 2 PID: 1635 Comm: sh Not tainted 5.7.0-rc5-00033-gb922183867f5 #14
	Hardware name: linux,dummy-virt (DT)
	Call trace:
	 dump_backtrace+0x0/0x1b0
	 show_stack+0x20/0x30
	 dump_stack+0xc0/0x10c
	 panic+0x16c/0x368
	 __warn+0x120/0x160
	 report_bug+0xc8/0x160
	 bug_handler+0x28/0x98
	 brk_handler+0x70/0xd0
	 do_debug_exception+0xcc/0x1ac
	 el1_sync_handler+0xe4/0x120
	 el1_sync+0x7c/0x100
	 ftrace_bug+0x204/0x238

Link: https://lkml.kernel.org/r/20200515100828.7091-1-cj.chengjian@huawei.com

Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-19 21:08:01 -04:00
Gustavo A. R. Silva
db78538c75 locking/lockdep: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200507185804.GA15036@embeddedor
2020-05-19 20:34:18 +02:00
Gustavo A. R. Silva
c50c75e9b8 perf/core: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200511201227.GA14041@embeddedor
2020-05-19 20:34:16 +02:00
Huaixin Chang
d505b8af58 sched: Defend cfs and rt bandwidth quota against overflow
When users write some huge number into cpu.cfs_quota_us or
cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of
schedulable checks.

to_ratio() could be altered to avoid unnecessary internal overflow, but
min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still
be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to
prevent overflow.

Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com
2020-05-19 20:34:14 +02:00
Muchun Song
dbe9337109 sched/cpuacct: Fix charge cpuacct.usage_sys
The user_mode(task_pt_regs(tsk)) always return true for
user thread, and false for kernel thread. So it means that
the cpuacct.usage_sys is the time that kernel thread uses
not the time that thread uses in the kernel mode. We can
try get_irq_regs() first, if it is NULL, then we can fall
back to task_pt_regs().

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200420070453.76815-1-songmuchun@bytedance.com
2020-05-19 20:34:14 +02:00
Gustavo A. R. Silva
04f5c362ec sched/fair: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200507192141.GA16183@embeddedor
2020-05-19 20:34:14 +02:00
Vincent Guittot
95d685935a sched/pelt: Sync util/runnable_sum with PELT window when propagating
update_tg_cfs_*() propagate the impact of the attach/detach of an entity
down into the cfs_rq hierarchy and must keep the sync with the current pelt
window.

Even if we can't sync child cfs_rq and its group se, we can sync the group
se and its parent cfs_rq with current position in the PELT window. In fact,
we must keep them sync in order to stay also synced with others entities
and group entities that are already attached to the cfs_rq.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200506155301.14288-1-vincent.guittot@linaro.org
2020-05-19 20:34:14 +02:00
Muchun Song
12aa258738 sched/cpuacct: Use __this_cpu_add() instead of this_cpu_ptr()
The cpuacct_charge() and cpuacct_account_field() are called with
rq->lock held, and this means preemption(and IRQs) are indeed
disabled, so it is safe to use __this_cpu_*() to allow for better
code-generation.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200507031039.32615-1-songmuchun@bytedance.com
2020-05-19 20:34:13 +02:00
Vincent Guittot
7d148be69e sched/fair: Optimize enqueue_task_fair()
enqueue_task_fair jumps to enqueue_throttle label when cfs_rq_of(se) is
throttled which means that se can't be NULL in such case and we can move
the label after the if (!se) statement. Futhermore, the latter can be
removed because se is always NULL when reaching this point.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20200513135502.4672-1-vincent.guittot@linaro.org
2020-05-19 20:34:13 +02:00
Peter Zijlstra
9013196a46 Merge branch 'sched/urgent' 2020-05-19 20:34:12 +02:00
Vincent Guittot
39f23ce07b sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list
Although not exactly identical, unthrottle_cfs_rq() and enqueue_task_fair()
are quite close and follow the same sequence for enqueuing an entity in the
cfs hierarchy. Modify unthrottle_cfs_rq() to use the same pattern as
enqueue_task_fair(). This fixes a problem already faced with the latter and
add an optimization in the last for_each_sched_entity loop.

Fixes: fe61468b2c (sched/fair: Fix enqueue_task_fair warning)
Reported-by Tao Zhou <zohooouoto@zoho.com.cn>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20200513135528.4742-1-vincent.guittot@linaro.org
2020-05-19 20:34:10 +02:00
Pavankumar Kondeti
ad32bb41fc sched/debug: Fix requested task uclamp values shown in procfs
The intention of commit 96e74ebf8d ("sched/debug: Add task uclamp
values to SCHED_DEBUG procfs") was to print requested and effective
task uclamp values. The requested values printed are read from p->uclamp,
which holds the last effective values. Fix this by printing the values
from p->uclamp_req.

Fixes: 96e74ebf8d ("sched/debug: Add task uclamp values to SCHED_DEBUG procfs")
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/1589115401-26391-1-git-send-email-pkondeti@codeaurora.org
2020-05-19 20:34:10 +02:00
Phil Auld
b34cb07dde sched/fair: Fix enqueue_task_fair() warning some more
sched/fair: Fix enqueue_task_fair warning some more

The recent patch, fe61468b2c (sched/fair: Fix enqueue_task_fair warning)
did not fully resolve the issues with the rq->tmp_alone_branch !=
&rq->leaf_cfs_rq_list warning in enqueue_task_fair. There is a case where
the first for_each_sched_entity loop exits due to on_rq, having incompletely
updated the list.  In this case the second for_each_sched_entity loop can
further modify se. The later code to fix up the list management fails to do
what is needed because se does not point to the sched_entity which broke out
of the first loop. The list is not fixed up because the throttled parent was
already added back to the list by a task enqueue in a parallel child hierarchy.

Address this by calling list_add_leaf_cfs_rq if there are throttled parents
while doing the second for_each_sched_entity loop.

Fixes: fe61468b2c ("sched/fair: Fix enqueue_task_fair warning")
Suggested-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200512135222.GC2201@lorien.usersys.redhat.com
2020-05-19 20:34:10 +02:00
Daniel Borkmann
1b66d25361 bpf: Add get{peer, sock}name attach types for sock_addr
As stated in 983695fa67 ("bpf: fix unconnected udp hooks"), the objective
for the existing cgroup connect/sendmsg/recvmsg/bind BPF hooks is to be
transparent to applications. In Cilium we make use of these hooks [0] in
order to enable E-W load balancing for existing Kubernetes service types
for all Cilium managed nodes in the cluster. Those backends can be local
or remote. The main advantage of this approach is that it operates as close
as possible to the socket, and therefore allows to avoid packet-based NAT
given in connect/sendmsg/recvmsg hooks we only need to xlate sock addresses.

This also allows to expose NodePort services on loopback addresses in the
host namespace, for example. As another advantage, this also efficiently
blocks bind requests for applications in the host namespace for exposed
ports. However, one missing item is that we also need to perform reverse
xlation for inet{,6}_getname() hooks such that we can return the service
IP/port tuple back to the application instead of the remote peer address.

The vast majority of applications does not bother about getpeername(), but
in a few occasions we've seen breakage when validating the peer's address
since it returns unexpectedly the backend tuple instead of the service one.
Therefore, this trivial patch allows to customise and adds a getpeername()
as well as getsockname() BPF cgroup hook for both IPv4 and IPv6 in order
to address this situation.

Simple example:

  # ./cilium/cilium service list
  ID   Frontend     Service Type   Backend
  1    1.2.3.4:80   ClusterIP      1 => 10.0.0.10:80

Before; curl's verbose output example, no getpeername() reverse xlation:

  # curl --verbose 1.2.3.4
  * Rebuilt URL to: 1.2.3.4/
  *   Trying 1.2.3.4...
  * TCP_NODELAY set
  * Connected to 1.2.3.4 (10.0.0.10) port 80 (#0)
  > GET / HTTP/1.1
  > Host: 1.2.3.4
  > User-Agent: curl/7.58.0
  > Accept: */*
  [...]

After; with getpeername() reverse xlation:

  # curl --verbose 1.2.3.4
  * Rebuilt URL to: 1.2.3.4/
  *   Trying 1.2.3.4...
  * TCP_NODELAY set
  * Connected to 1.2.3.4 (1.2.3.4) port 80 (#0)
  > GET / HTTP/1.1
  >  Host: 1.2.3.4
  > User-Agent: curl/7.58.0
  > Accept: */*
  [...]

Originally, I had both under a BPF_CGROUP_INET{4,6}_GETNAME type and exposed
peer to the context similar as in inet{,6}_getname() fashion, but API-wise
this is suboptimal as it always enforces programs having to test for ctx->peer
which can easily be missed, hence BPF_CGROUP_INET{4,6}_GET{PEER,SOCK}NAME split.
Similarly, the checked return code is on tnum_range(1, 1), but if a use case
comes up in future, it can easily be changed to return an error code instead.
Helper and ctx member access is the same as with connect/sendmsg/etc hooks.

  [0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.c

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/61a479d759b2482ae3efb45546490bacd796a220.1589841594.git.daniel@iogearbox.net
2020-05-19 11:32:04 -07:00
Domenico Andreoli
c4f39a6c74 PM: hibernate: Split off snapshot dev option
Make it possible to reduce the attack surface in case the snapshot
device is not to be used from userspace.

Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-19 17:48:08 +02:00
Domenico Andreoli
ab7e9b067f PM: hibernate: Incorporate concurrency handling
Hibernation concurrency handling is currently delegated to user.c,
where it's also used for regulating the access to the snapshot device.

In the prospective of making user.c a separate configuration option,
such mutual exclusion is brought into hibernate.c and made available
through accessor helpers hereby introduced.

Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-19 17:48:08 +02:00
David Howells
e7d553d69c pipe: Add notification lossage handling
Add handling for loss of notifications by having read() insert a
loss-notification message after it has read the pipe buffer that was last
in the ring when the loss occurred.

Lossage can come about either by running out of notification descriptors or
by running out of space in the pipe ring.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-19 15:40:28 +01:00
David Howells
8cfba76383 pipe: Allow buffers to be marked read-whole-or-error for notifications
Allow a buffer to be marked such that read() must return the entire buffer
in one go or return ENOBUFS.  Multiple buffers can be amalgamated into a
single read, but a short read will occur if the next "whole" buffer won't
fit.

This is useful for watch queue notifications to make sure we don't split a
notification across multiple reads, especially given that we need to
fabricate an overrun record under some circumstances - and that isn't in
the buffers.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-19 15:38:18 +01:00
David Howells
c73be61ced pipe: Add general notification queue support
Make it possible to have a general notification queue built on top of a
standard pipe.  Notifications are 'spliced' into the pipe and then read
out.  splice(), vmsplice() and sendfile() are forbidden on pipes used for
notifications as post_one_notification() cannot take pipe->mutex.  This
means that notifications could be posted in between individual pipe
buffers, making iov_iter_revert() difficult to effect.

The way the notification queue is used is:

 (1) An application opens a pipe with a special flag and indicates the
     number of messages it wishes to be able to queue at once (this can
     only be set once):

	pipe2(fds, O_NOTIFICATION_PIPE);
	ioctl(fds[0], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);

 (2) The application then uses poll() and read() as normal to extract data
     from the pipe.  read() will return multiple notifications if the
     buffer is big enough, but it will not split a notification across
     buffers - rather it will return a short read or EMSGSIZE.

     Notification messages include a length in the header so that the
     caller can split them up.

Each message has a header that describes it:

	struct watch_notification {
		__u32	type:24;
		__u32	subtype:8;
		__u32	info;
	};

The type indicates the source (eg. mount tree changes, superblock events,
keyring changes, block layer events) and the subtype indicates the event
type (eg. mount, unmount; EIO, EDQUOT; link, unlink).  The info field
indicates a number of things, including the entry length, an ID assigned to
a watchpoint contributing to this buffer and type-specific flags.

Supplementary data, such as the key ID that generated an event, can be
attached in additional slots.  The maximum message size is 127 bytes.
Messages may not be padded or aligned, so there is no guarantee, for
example, that the notification type will be on a 4-byte bounary.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-19 15:08:24 +01:00
Thomas Gleixner
66e9b07171 kprobes: Prevent probes in .noinstr.text section
Instrumentation is forbidden in the .noinstr.text section. Make kprobes
respect this.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200505134100.179862032@linutronix.de
2020-05-19 15:56:20 +02:00
Thomas Gleixner
b1fcf9b83c rcu: Provide __rcu_is_watching()
Same as rcu_is_watching() but without the preempt_disable/enable() pair
inside the function. It is merked noinstr so it ends up in the
non-instrumentable text section.

This is useful for non-preemptible code especially in the low level entry
section. Using rcu_is_watching() there results in a call to the
preempt_schedule_notrace() thunk which triggers noinstr section warnings in
objtool.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200512213810.518709291@linutronix.de
2020-05-19 15:51:21 +02:00
Thomas Gleixner
8ae0ae6737 rcu: Provide rcu_irq_exit_preempt()
Interrupts and exceptions invoke rcu_irq_enter() on entry and need to
invoke rcu_irq_exit() before they either return to the interrupted code or
invoke the scheduler due to preemption.

The general assumption is that RCU idle code has to have preemption
disabled so that a return from interrupt cannot schedule. So the return
from interrupt code invokes rcu_irq_exit() and preempt_schedule_irq().

If there is any imbalance in the rcu_irq/nmi* invocations or RCU idle code
had preemption enabled then this goes unnoticed until the CPU goes idle or
some other RCU check is executed.

Provide rcu_irq_exit_preempt() which can be invoked from the
interrupt/exception return code in case that preemption is enabled. It
invokes rcu_irq_exit() and contains a few sanity checks in case that
CONFIG_PROVE_RCU is enabled to catch such issues directly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134904.364456424@linutronix.de
2020-05-19 15:51:21 +02:00
Paul E. McKenney
9ea366f669 rcu: Make RCU IRQ enter/exit functions rely on in_nmi()
The rcu_nmi_enter_common() and rcu_nmi_exit_common() functions take an
"irq" parameter that indicates whether these functions have been invoked from
an irq handler (irq==true) or an NMI handler (irq==false).

However, recent changes have applied notrace to a few critical functions
such that rcu_nmi_enter_common() and rcu_nmi_exit_common() many now rely on
in_nmi().  Note that in_nmi() works no differently than before, but rather
that tracing is now prohibited in code regions where in_nmi() would
incorrectly report NMI state.

Therefore remove the "irq" parameter and inline rcu_nmi_enter_common() and
rcu_nmi_exit_common() into rcu_nmi_enter() and rcu_nmi_exit(),
respectively.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.617130349@linutronix.de
2020-05-19 15:51:21 +02:00
Thomas Gleixner
ff5c4f5cad rcu/tree: Mark the idle relevant functions noinstr
These functions are invoked from context tracking and other places in the
low level entry code. Move them into the .noinstr.text section to exclude
them from instrumentation.

Mark the places which are safe to invoke traceable functions with
instrumentation_begin/end() so objtool won't complain.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20200505134100.575356107@linutronix.de
2020-05-19 15:51:20 +02:00
Peter Zijlstra
178ba00c35 sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception
SuperH is the last remaining user of arch_ftrace_nmi_{enter,exit}(),
remove it from the generic code and into the SuperH code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200505134101.248881738@linutronix.de
2020-05-19 15:51:18 +02:00
Peter Zijlstra
e616cb8daa lockdep: Always inline lockdep_{off,on}()
These functions are called {early,late} in nmi_{enter,exit} and should
not be traced or probed. They are also puny, so 'inline' them.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.048523500@linutronix.de
2020-05-19 15:51:18 +02:00
Peter Zijlstra
b0f51883f5 printk: Disallow instrumenting print_nmi_enter()
It happens early in nmi_enter(), no tracing, probing or other funnies
allowed. Specifically as nmi_enter() will be used in do_debug(), which
would cause recursive exceptions when kprobed.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134101.139720912@linutronix.de
2020-05-19 15:51:16 +02:00
Petr Mladek
8c4e93c362 printk: Prepare for nested printk_nmi_enter()
There is plenty of space in the printk_context variable. Reserve one byte
there for the NMI context to be on the safe side.

It should never overflow. The BUG_ON(in_nmi() == NMI_MASK) in nmi_enter()
will trigger much earlier.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.681374113@linutronix.de
2020-05-19 15:51:16 +02:00
Thomas Gleixner
1ed0948eea Merge tag 'noinstr-lds-2020-05-19' into core/rcu
Get the noinstr section and annotation markers to base the RCU parts on.
2020-05-19 15:50:34 +02:00
Peter Zijlstra
c86e9b987c lockdep: Prepare for noinstr sections
Force inlining and prevent instrumentation of all sorts by marking the
functions which are invoked from low level entry code with 'noinstr'.

Split the irqflags tracking into two parts. One which does the heavy
lifting while RCU is watching and the final one which can be invoked after
RCU is turned off.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134100.484532537@linutronix.de
2020-05-19 15:47:21 +02:00
Thomas Gleixner
0995a5dfbe tracing: Provide lockdep less trace_hardirqs_on/off() variants
trace_hardirqs_on/off() is only partially safe vs. RCU idle. The tracer
core itself is safe, but the resulting tracepoints can be utilized by
e.g. BPF which is unsafe.

Provide variants which do not contain the lockdep invocation so the lockdep
and tracer invocations can be split at the call site and placed
properly. This is required because lockdep needs to be aware of the state
before switching away from RCU idle and after switching to RCU idle because
these transitions can take locks.

As these code pathes are going to be non-instrumentable the tracer can be
invoked after RCU is turned on and before the switch to RCU idle. So for
these new variants there is no need to invoke the rcuidle aware tracer
functions.

Name them so they match the lockdep counterparts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134100.270771162@linutronix.de
2020-05-19 15:47:21 +02:00
Alexey Gladkov
9d78edeaec proc: proc_pid_ns takes super_block as an argument
syzbot found that

  touch /proc/testfile

causes NULL pointer dereference at tomoyo_get_local_path()
because inode of the dentry is NULL.

Before c59f415a7c, Tomoyo received pid_ns from proc's s_fs_info
directly. Since proc_pid_ns() can only work with inode, using it in
the tomoyo_get_local_path() was wrong.

To avoid creating more functions for getting proc_ns, change the
argument type of the proc_pid_ns() function. Then, Tomoyo can use
the existing super_block to get pid_ns.

Link: https://lkml.kernel.org/r/0000000000002f0c7505a5b0e04c@google.com
Link: https://lkml.kernel.org/r/20200518180738.2939611-1-gladkov.alexey@gmail.com
Reported-by: syzbot+c1af344512918c61362c@syzkaller.appspotmail.com
Fixes: c59f415a7c ("Use proc_pid_ns() to get pid_namespace from the proc superblock")
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-05-19 07:07:50 -05:00
Vincent Whitchurch
2318976619 ARM: 8976/1: module: allow arch overrides for .init section names
ARM stores unwind information for .init.text in sections named
.ARM.extab.init.text and .ARM.exidx.init.text.  Since those aren't
currently recognized as init sections, they're allocated along with the
core section, and relocation fails if the core and the init section are
allocated from different regions and can't reach other.

  final section addresses:
        ...
        0x7f800000 .init.text
        ..
        0xcbb54078 .ARM.exidx.init.text
        ..

 section 16 reloc 0 sym '': relocation 42 out of range (0xcbb54078 ->
 0x7f800000)

Allow architectures to override the section name so that ARM can fix
this.

Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-05-19 11:42:16 +01:00
Vincent Chen
f83b04d36e
kgdb: Add kgdb_has_hit_break function
The break instruction in RISC-V does not have an immediate value field, so
the kernel cannot identify the purpose of each trap exception through the
opcode. This makes the existing identification schemes in other
architecture unsuitable for the RISC-V kernel. To solve this problem, this
patch adds kgdb_has_hit_break(), which can help RISC-V kernel identify
the KGDB trap exception.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-05-18 11:38:09 -07:00
Douglas Anderson
220995622d kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles
We want to enable kgdb to debug the early parts of the kernel.
Unfortunately kgdb normally is a client of the tty API in the kernel
and serial drivers don't register to the tty layer until fairly late
in the boot process.

Serial drivers do, however, commonly register a boot console.  Let's
enable the kgdboc driver to work with boot consoles to provide early
debugging.

This change co-opts the existing read() function pointer that's part
of "struct console".  It's assumed that if a boot console (with the
flag CON_BOOT) has implemented read() that both the read() and write()
function are polling functions.  That means they work without
interrupts and read() will return immediately (with 0 bytes read) if
there's nothing to read.  This should be a safe assumption since it
appears that no current boot consoles implement read() right now and
there seems no reason to do so unless they wanted to support
"kgdboc_earlycon".

The normal/expected way to make all this work is to use
"kgdboc_earlycon" and "kgdboc" together.  You should point them both
to the same physical serial connection.  At boot time, as the system
transitions from the boot console to the normal console (and registers
a tty), kgdb will switch over.

One awkward part of all this, though, is that there can be a window
where the boot console goes away and we can't quite transtion over to
the main kgdboc that uses the tty layer.  There are two main problems:

1. The act of registering the tty doesn't cause any call into kgdboc
   so there is a window of time when the tty is there but kgdboc's
   init code hasn't been called so we can't transition to it.

2. On some serial drivers the normal console inits (and replaces the
   boot console) quite early in the system.  Presumably these drivers
   were coded up before earlycon worked as well as it does today and
   probably they don't need to do this anymore, but it causes us
   problems nontheless.

Problem #1 is not too big of a deal somewhat due to the luck of probe
ordering.  kgdboc is last in the tty/serial/Makefile so its probe gets
right after all other tty devices.  It's not fun to rely on this, but
it does work for the most part.

Problem #2 is a big deal, but only for some serial drivers.  Other
serial drivers end up registering the console (which gets rid of the
boot console) and tty at nearly the same time.

The way we'll deal with the window when the system has stopped using
the boot console and the time when we're setup using the tty is to
keep using the boot console.  This may sound surprising, but it has
been found to work well in practice.  If it doesn't work, it shouldn't
be too hard for a given serial driver to make it keep working.
Specifically, it's expected that the read()/write() function provided
in the boot console should be the same (or nearly the same) as the
normal kgdb polling functions.  That means continuing to use them
should work just fine.  To make things even more likely to work work
we'll also trap the recently added exit() function in the boot console
we're using and delay any calls to it until we're all done with the
boot console.

NOTE: there could be ways to use all this in weird / unexpected ways.
If you do something like this, it's a bit of a buyer beware situation.
Specifically:
- If you specify only "kgdboc_earlycon" but not "kgdboc" then
  (depending on your serial driver) things will probably work OK, but
  you'll get a warning printed the first time you use kgdb after the
  boot console is gone.  You'd only be able to do this, of course, if
  the serial driver you're running atop provided an early boot console.
- If your "kgdboc_earlycon" and "kgdboc" devices are not the same
  device things should work OK, but it'll be your job to switch over
  which device you're monitoring (including figuring out how to switch
  over gdb in-flight if you're using it).

When trying to enable "kgdboc_earlycon" it should be noted that the
names that are registered through the boot console layer and the tty
layer are not the same for the same port.  For example when debugging
on one board I'd need to pass "kgdboc_earlycon=qcom_geni
kgdboc=ttyMSM0" to enable things properly.  Since digging up the boot
console name is a pain and there will rarely be more than one boot
console enabled, you can provide the "kgdboc_earlycon" parameter
without specifying the name of the boot console.  In this case we'll
just pick the first boot that implements read() that we find.

This new "kgdboc_earlycon" parameter should be contrasted to the
existing "ekgdboc" parameter.  While both provide a way to debug very
early, the usage and mechanisms are quite different.  Specifically
"kgdboc_earlycon" is meant to be used in tandem with "kgdboc" and
there is a transition from one to the other.  The "ekgdboc" parameter,
on the other hand, replaces the "kgdboc" parameter.  It runs the same
logic as the "kgdboc" parameter but just relies on your TTY driver
being present super early.  The only known usage of the old "ekgdboc"
parameter is documented as "ekgdboc=kbd earlyprintk=vga".  It should
be noted that "kbd" has special treatment allowing it to init early as
a tty device.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.8.I8fba5961bf452ab92350654aa61957f23ecf0100@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18 17:49:27 +01:00
Douglas Anderson
3ca676e4ca kgdb: Prevent infinite recursive entries to the debugger
If we detect that we recursively entered the debugger we should hack
our I/O ops to NULL so that the panic() in the next line won't
actually cause another recursion into the debugger.  The first line of
kgdb_panic() will check this and return.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18 17:49:27 +01:00
Douglas Anderson
b1a57bbfcc kgdb: Delay "kgdbwait" to dbg_late_init() by default
Using kgdb requires at least some level of architecture-level
initialization.  If nothing else, it relies on the architecture to
pass breakpoints / crashes onto kgdb.

On some architectures this all works super early, specifically it
starts working at some point in time before Linux parses
early_params's.  On other architectures it doesn't.  A survey of a few
platforms:

a) x86: Presumably it all works early since "ekgdboc" is documented to
   work here.
b) arm64: Catching crashes works; with a simple patch breakpoints can
   also be made to work.
c) arm: Nothing in kgdb works until
   paging_init() -> devicemaps_init() -> early_trap_init()

Let's be conservative and, by default, process "kgdbwait" (which tells
the kernel to drop into the debugger ASAP at boot) a bit later at
dbg_late_init() time.  If an architecture has tested it and wants to
re-enable super early debugging, they can select the
ARCH_HAS_EARLY_DEBUG KConfig option.  We'll do this for x86 to start.
It should be noted that dbg_late_init() is still called quite early in
the system.

Note that this patch doesn't affect when kgdb runs its init.  If kgdb
is set to initialize early it will still initialize when parsing
early_param's.  This patch _only_ inhibits the initial breakpoint from
"kgdbwait".  This means:

* Without any extra patches arm64 platforms will at least catch
  crashes after kgdb inits.
* arm platforms will catch crashes (and could handle a hardcoded
  kgdb_breakpoint()) any time after early_trap_init() runs, even
  before dbg_late_init().

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200507130644.v4.4.I3113aea1b08d8ce36dc3720209392ae8b815201b@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18 17:49:27 +01:00
Will Deacon
aa7a65ae5b scs: Remove references to asm/scs.h from core code
asm/scs.h is no longer needed by the core code, so remove a redundant
header inclusion and update the stale Kconfig text.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-18 17:47:45 +01:00
Will Deacon
88485be531 scs: Move scs_overflow_check() out of architecture code
There is nothing architecture-specific about scs_overflow_check() as
it's just a trivial wrapper around scs_corrupted().

For parity with task_stack_end_corrupted(), rename scs_corrupted() to
task_scs_end_corrupted() and call it from schedule_debug() when
CONFIG_SCHED_STACK_END_CHECK_is enabled, which better reflects its
purpose as a debug feature to catch inadvertent overflow of the SCS.
Finally, remove the unused scs_overflow_check() function entirely.

This has absolutely no impact on architectures that do not support SCS
(currently arm64 only).

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-18 17:47:40 +01:00
Will Deacon
bee348fab0 scs: Move accounting into alloc/free functions
There's no need to perform the shadow stack page accounting independently
of the lifetime of the underlying allocation, so call the accounting code
from the {alloc,free}() functions and simplify the code in the process.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-18 17:47:33 +01:00
Will Deacon
51189c7a7e arm64: scs: Store absolute SCS stack pointer value in thread_info
Storing the SCS information in thread_info as a {base,offset} pair
introduces an additional load instruction on the ret-to-user path,
since the SCS stack pointer in x18 has to be converted back to an offset
by subtracting the base.

Replace the offset with the absolute SCS stack pointer value instead
and avoid the redundant load.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-18 17:47:22 +01:00
Douglas Anderson
202164fbfa kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb
In commit 81eaadcae8 ("kgdboc: disable the console lock when in
kgdb") we avoided the WARN_CONSOLE_UNLOCKED() yell when we were in
kgdboc.  That still works fine, but it turns out that we get a similar
yell when using other I/O drivers.  One example is the "I/O driver"
for the kgdb test suite (kgdbts).  When I enabled that I again got the
same yells.

Even though "kgdbts" doesn't actually interact with the user over the
console, using it still causes kgdb to print to the consoles.  That
trips the same warning:
  con_is_visible+0x60/0x68
  con_scroll+0x110/0x1b8
  lf+0x4c/0xc8
  vt_console_print+0x1b8/0x348
  vkdb_printf+0x320/0x89c
  kdb_printf+0x68/0x90
  kdb_main_loop+0x190/0x860
  kdb_stub+0x2cc/0x3ec
  kgdb_cpu_enter+0x268/0x744
  kgdb_handle_exception+0x1a4/0x200
  kgdb_compiled_brk_fn+0x34/0x44
  brk_handler+0x7c/0xb8
  do_debug_exception+0x1b4/0x228

Let's increment/decrement the "ignore_console_lock_warning" variable
all the time when we enter the debugger.

This will allow us to later revert commit 81eaadcae8 ("kgdboc:
disable the console lock when in kgdb").

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.1.Ied2b058357152ebcc8bf68edd6f20a11d98d7d4e@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18 15:28:16 +01:00
Ravi Bangoria
29da4f91c0 powerpc/watchpoint: Don't allow concurrent perf and ptrace events
With Book3s DAWR, ptrace and perf watchpoints on powerpc behaves
differently. Ptrace watchpoint works in one-shot mode and generates
signal before executing instruction. It's ptrace user's job to
single-step the instruction and re-enable the watchpoint. OTOH, in
case of perf watchpoint, kernel emulates/single-steps the instruction
and then generates event. If perf and ptrace creates two events with
same or overlapping address ranges, it's ambiguous to decide who
should single-step the instruction. Because of this issue, don't
allow perf and ptrace watchpoint at the same time if their address
range overlaps.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-15-ravi.bangoria@linux.ibm.com
2020-05-19 00:14:45 +10:00
Jonathan Corbet
fdb1b5e089 Revert "docs: sysctl/kernel: document ngroups_max"
This reverts commit 2f4c33063a.

The changes here were fine, but there's a non-documentation change to
sysctl.c that makes messes elsewhere; those changes should have been done
independently.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-05-18 06:19:25 -06:00
Bartosz Golaszewski
337cbeb2c1 genirq/irq_sim: Simplify the API
The interrupt simulator API exposes a lot of custom data structures and
functions and doesn't reuse the interfaces already exposed by the irq
subsystem. This patch tries to address it.

We hide all the simulator-related data structures from users and instead
rely on the well-known irq domain. When creating the interrupt simulator
the user receives a pointer to a newly created irq_domain and can use it
to create mappings for simulated interrupts.

It is also possible to pass a handle to fwnode when creating the simulator
domain and retrieve it using irq_find_matching_fwnode().

The irq_sim_fire() function is dropped as well. Instead we implement the
irq_get/set_irqchip_state interface.

We modify the two modules that use the simulator at the same time as
adding these changes in order to reduce the intermediate bloat that would
result when trying to migrate the drivers in separate patches.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO
Link: https://lore.kernel.org/r/20200514083901.23445-3-brgl@bgdev.pl
2020-05-18 10:30:21 +01:00
Bartosz Golaszewski
5c8f77a278 irqdomain: Make irq_domain_reset_irq_data() available to non-hierarchical users
irq_domain_reset_irq_data() doesn't modify the parent data, so it can be
made available even if irq domain hierarchy is not being built. We'll
subsequently use it in irq_sim code.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20200514083901.23445-2-brgl@bgdev.pl
2020-05-18 10:29:26 +01:00
Jan Kara
870c153cf0 blktrace: Report pid with note messages
Currently informational messages within block trace do not have PID
information of the process reporting the message included. With BFQ it
is sometimes useful to have the information and there's no good reason
to omit the information from the trace. So just fill in pid information
when generating note message.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-16 14:29:39 -06:00
Daniel Borkmann
2ec0616e87 bpf: Fix check_return_code to only allow [0,1] in trace_iter progs
As per 15d83c4d7c ("bpf: Allow loading of a bpf_iter program") we only
allow a range of [0,1] for return codes. Therefore BPF_TRACE_ITER relies
on the default tnum_range(0, 1) which is set in range var. On recent merge
of net into net-next commit e92888c72f ("bpf: Enforce returning 0 for
fentry/fexit progs") got pulled in and caused a merge conflict with the
changes from 15d83c4d7c. The resolution had a snall hiccup in that it
removed the [0,1] range restriction again so that BPF_TRACE_ITER would
have no enforcement. Fix it by adding it back.

Fixes: da07f52d3c ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
2020-05-16 00:48:02 +02:00
David S. Miller
da07f52d3c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Move the bpf verifier trace check into the new switch statement in
HEAD.

Resolve the overlapping changes in hinic, where bug fixes overlap
the addition of VF support.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-15 13:48:59 -07:00
Linus Torvalds
f85c1598dd Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:

 1) Fix sk_psock reference count leak on receive, from Xiyu Yang.

 2) CONFIG_HNS should be invisible, from Geert Uytterhoeven.

 3) Don't allow locking route MTUs in ipv6, RFCs actually forbid this,
    from Maciej Żenczykowski.

 4) ipv4 route redirect backoff wasn't actually enforced, from Paolo
    Abeni.

 5) Fix netprio cgroup v2 leak, from Zefan Li.

 6) Fix infinite loop on rmmod in conntrack, from Florian Westphal.

 7) Fix tcp SO_RCVLOWAT hangs, from Eric Dumazet.

 8) Various bpf probe handling fixes, from Daniel Borkmann.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (68 commits)
  selftests: mptcp: pm: rm the right tmp file
  dpaa2-eth: properly handle buffer size restrictions
  bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
  bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range
  bpf: Restrict bpf_probe_read{, str}() only to archs where they work
  MAINTAINERS: Mark networking drivers as Maintained.
  ipmr: Add lockdep expression to ipmr_for_each_table macro
  ipmr: Fix RCU list debugging warning
  drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c
  net: phy: broadcom: fix BCM54XX_SHD_SCR3_TRDDAPD value for BCM54810
  tcp: fix error recovery in tcp_zerocopy_receive()
  MAINTAINERS: Add Jakub to networking drivers.
  MAINTAINERS: another add of Karsten Graul for S390 networking
  drivers: ipa: fix typos for ipa_smp2p structure doc
  pppoe: only process PADT targeted at local interfaces
  selftests/bpf: Enforce returning 0 for fentry/fexit programs
  bpf: Enforce returning 0 for fentry/fexit progs
  net: stmmac: fix num_por initialization
  security: Fix the default value of secid_to_secctx hook
  libbpf: Fix register naming in PT_REGS s390 macros
  ...
2020-05-15 13:10:06 -07:00
Douglas Anderson
b5945214b7 kernel/cpu_pm: Fix uninitted local in cpu_pm
cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e00 ("cpu_pm: Add cpu power management notifiers")
Cc: stable@vger.kernel.org
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-05-15 11:44:34 -07:00
Stephen Kitt
2f4c33063a docs: sysctl/kernel: document ngroups_max
This is a read-only export of NGROUPS_MAX, so this patch also changes
the declarations in kernel/sysctl.c to const.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200515160222.7994-1-steve@sk2.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-05-15 11:24:25 -06:00
Sami Tolvanen
5bbaf9d1fc scs: Add support for stack usage debugging
Implements CONFIG_DEBUG_STACK_USAGE for shadow stacks. When enabled,
also prints out the highest shadow stack usage per process.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
[will: rewrote most of scs_check_usage()]
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-15 16:35:49 +01:00
Sami Tolvanen
628d06a48f scs: Add page accounting for shadow call stack allocations
This change adds accounting for the memory allocated for shadow stacks.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-15 16:35:49 +01:00
Sami Tolvanen
d08b9f0ca6 scs: Add support for Clang's Shadow Call Stack (SCS)
This change adds generic support for Clang's Shadow Call Stack,
which uses a shadow stack to protect return addresses from being
overwritten by an attacker. Details are available here:

  https://clang.llvm.org/docs/ShadowCallStack.html

Note that security guarantees in the kernel differ from the ones
documented for user space. The kernel must store addresses of
shadow stacks in memory, which means an attacker capable reading
and writing arbitrary memory may be able to locate them and hijack
control flow by modifying the stacks.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[will: Numerous cosmetic changes]
Signed-off-by: Will Deacon <will@kernel.org>
2020-05-15 16:35:45 +01:00
Alexei Starovoitov
2c78ee898d bpf: Implement CAP_BPF
Implement permissions as stated in uapi/linux/capability.h
In order to do that the verifier allow_ptr_leaks flag is split
into four flags and they are set as:
  env->allow_ptr_leaks = bpf_allow_ptr_leaks();
  env->bypass_spec_v1 = bpf_bypass_spec_v1();
  env->bypass_spec_v4 = bpf_bypass_spec_v4();
  env->bpf_capable = bpf_capable();

The first three currently equivalent to perfmon_capable(), since leaking kernel
pointers and reading kernel memory via side channel attacks is roughly
equivalent to reading kernel memory with cap_perfmon.

'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and
other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions,
subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the
verifier, run time mitigations in bpf array, and enables indirect variable
access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code
by the verifier.

That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN
will have speculative checks done by the verifier and other spectre mitigation
applied. Such networking BPF program will not be able to leak kernel pointers
and will not be able to access arbitrary kernel memory.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com
2020-05-15 17:29:41 +02:00
Daniel Borkmann
b2a5212fb6 bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
Usage of plain %s conversion specifier in bpf_trace_printk() suffers from the
very same issue as bpf_probe_read{,str}() helpers, that is, it is broken on
archs with overlapping address ranges.

While the helpers have been addressed through work in 6ae08ae3de ("bpf: Add
probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers"), we need
an option for bpf_trace_printk() as well to fix it.

Similarly as with the helpers, force users to make an explicit choice by adding
%pks and %pus specifier to bpf_trace_printk() which will then pick the corresponding
strncpy_from_unsafe*() variant to perform the access under KERNEL_DS or USER_DS.
The %pk* (kernel specifier) and %pu* (user specifier) can later also be extended
for other objects aside strings that are probed and printed under tracing, and
reused out of other facilities like bpf_seq_printf() or BTF based type printing.

Existing behavior of %s for current users is still kept working for archs where it
is not broken and therefore gated through CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
For archs not having this property we fall-back to pick probing under KERNEL_DS as
a sensible default.

Fixes: 8d3b7dce86 ("bpf: add support for %s specifier to bpf_trace_printk()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-4-daniel@iogearbox.net
2020-05-15 08:10:36 -07:00
Daniel Borkmann
47cc0ed574 bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range
Given bpf_probe_read{,str}() BPF helpers are now only available under
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE, we need to add the drop-in
replacements of bpf_probe_read_{kernel,user}_str() to do_refine_retval_range()
as well to avoid hitting the same issue as in 849fa50662 ("bpf/verifier:
refine retval R0 state for bpf_get_stack helper").

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-3-daniel@iogearbox.net
2020-05-15 08:10:36 -07:00
Daniel Borkmann
0ebeea8ca8 bpf: Restrict bpf_probe_read{, str}() only to archs where they work
Given the legacy bpf_probe_read{,str}() BPF helpers are broken on archs
with overlapping address ranges, we should really take the next step to
disable them from BPF use there.

To generally fix the situation, we've recently added new helper variants
bpf_probe_read_{user,kernel}() and bpf_probe_read_{user,kernel}_str().
For details on them, see 6ae08ae3de ("bpf: Add probe_read_{user, kernel}
and probe_read_{user,kernel}_str helpers").

Given bpf_probe_read{,str}() have been around for ~5 years by now, there
are plenty of users at least on x86 still relying on them today, so we
cannot remove them entirely w/o breaking the BPF tracing ecosystem.

However, their use should be restricted to archs with non-overlapping
address ranges where they are working in their current form. Therefore,
move this behind a CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE and
have x86, arm64, arm select it (other archs supporting it can follow-up
on it as well).

For the remaining archs, they can workaround easily by relying on the
feature probe from bpftool which spills out defines that can be used out
of BPF C code to implement the drop-in replacement for old/new kernels
via: bpftool feature probe macro

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/bpf/20200515101118.6508-2-daniel@iogearbox.net
2020-05-15 08:10:36 -07:00
Emil Velikov
0ca650c430 rcu: constify sysrq_key_op
With earlier commits, the API no longer discards the const-ness of the
sysrq_key_op. As such we can add the notation.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-kernel@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: rcu@vger.kernel.org
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://lore.kernel.org/r/20200513214351.2138580-11-emil.l.velikov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:53:20 +02:00
Emil Velikov
6400b5a0f6 kernel/power: constify sysrq_key_op
With earlier commits, the API no longer discards the const-ness of the
sysrq_key_op. As such we can add the notation.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-kernel@vger.kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <len.brown@intel.com>
Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://lore.kernel.org/r/20200513214351.2138580-10-emil.l.velikov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:53:20 +02:00
Emil Velikov
c69b470eb8 kdb: constify sysrq_key_op
With earlier commits, the API no longer discards the const-ness of the
sysrq_key_op. As such we can add the notation.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-kernel@vger.kernel.org
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: kgdb-bugreport@lists.sourceforge.net
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://lore.kernel.org/r/20200513214351.2138580-9-emil.l.velikov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 14:53:20 +02:00
Jesper Dangaard Brouer
db612f749e xdp: Cpumap redirect use frame_sz and increase skb_tailroom
Knowing the memory size backing the packet/xdp_frame data area, and
knowing it already have reserved room for skb_shared_info, simplifies
using build_skb significantly.

With this change we no-longer lie about the SKB truesize, but more
importantly a significant larger skb_tailroom is now provided, e.g. when
drivers uses a full PAGE_SIZE. This extra tailroom (in linear area) can be
used by the network stack when coalescing SKBs (e.g. in skb_try_coalesce,
see TCP cases where tcp_queue_rcv() can 'eat' skb).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158945337822.97035.13557959180460986059.stgit@firesoul
2020-05-14 21:21:54 -07:00
David S. Miller
d00f26b623 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-05-14

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Merged tag 'perf-for-bpf-2020-05-06' from tip tree that includes CAP_PERFMON.

2) support for narrow loads in bpf_sock_addr progs and additional
   helpers in cg-skb progs, from Andrey.

3) bpf benchmark runner, from Andrii.

4) arm and riscv JIT optimizations, from Luke.

5) bpf iterator infrastructure, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-14 20:31:21 -07:00
Andrii Nakryiko
c70f34a8ac bpf: Fix bpf_iter's task iterator logic
task_seq_get_next might stop prematurely if get_pid_task() fails to get
task_struct. Failure to do so doesn't mean that there are no more tasks with
higher pids. Procfs's iteration algorithm (see next_tgid in fs/proc/base.c)
does a retry in such case. After this fix, instead of stopping prematurely
after about 300 tasks on my server, bpf_iter program now returns >4000, which
sounds much closer to reality.

Fixes: eaaacd2391 ("bpf: Add task and task/file iterator targets")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200514055137.1564581-1-andriin@fb.com
2020-05-14 18:37:32 -07:00
Yonghong Song
e92888c72f bpf: Enforce returning 0 for fentry/fexit progs
Currently, tracing/fentry and tracing/fexit prog
return values are not enforced. In trampoline codes,
the fentry/fexit prog return values are ignored.
Let us enforce it to be 0 to avoid confusion and
allows potential future extension.

This patch also explicitly added return value
checking for tracing/raw_tp, tracing/fmod_ret,
and freplace programs such that these program
return values can be anything. The purpose are
two folds:
 1. to make it explicit about return value expectations
    for these programs in verifier.
 2. for tracing prog_type, if a future attach type
    is added, the default is -ENOTSUPP which will
    enforce to specify return value ranges explicitly.

Fixes: fec56f5890 ("bpf: Introduce BPF trampoline")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200514053206.1298415-1-yhs@fb.com
2020-05-14 12:50:10 -07:00
Andrii Nakryiko
333291ce50 bpf: Fix bug in mmap() implementation for BPF array map
mmap() subsystem allows user-space application to memory-map region with
initial page offset. This wasn't taken into account in initial implementation
of BPF array memory-mapping. This would result in wrong pages, not taking into
account requested page shift, being memory-mmaped into user-space. This patch
fixes this gap and adds a test for such scenario.

Fixes: fc9702273e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200512235925.3817805-1-andriin@fb.com
2020-05-14 12:40:04 -07:00
Linus Torvalds
8c1684bb81 for-linus-2020-05-13
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Merge tag 'for-linus-2020-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull thread fix from Christian Brauner:
 "This contains a single fix for all exported legacy fork helpers to
  block accidental access to clone3() features in the upper 32 bits of
  their respective flags arguments.

  I got Cced on a glibc issue where someone reported consistent failures
  for the legacy clone() syscall on ppc64le when sign extension was
  performed (since the clone() syscall in glibc exposes the flags
  argument as an int whereas the kernel uses unsigned long).

  The legacy clone() syscall is odd in a bunch of ways and here two
  things interact:

   - First, legacy clone's flag argument is word-size dependent, i.e.
     it's an unsigned long whereas most system calls with flag arguments
     use int or unsigned int.

   - Second, legacy clone() ignores unknown and deprecated flags.

  The two of them taken together means that users on 64bit systems can
  pass garbage for the upper 32bit of the clone() syscall since forever
  and things would just work fine.

  The following program compiled on a 64bit kernel prior to v5.7-rc1
  will succeed and will fail post v5.7-rc1 with EBADF:

    int main(int argc, char *argv[])
    {
          pid_t pid;

          /* Note that legacy clone() has different argument ordering on
           * different architectures so this won't work everywhere.
           *
           * Only set the upper 32 bits.
           */
          pid = syscall(__NR_clone, 0xffffffff00000000 | SIGCHLD,
                        NULL, NULL, NULL, NULL);
          if (pid < 0)
                  exit(EXIT_FAILURE);
          if (pid == 0)
                  exit(EXIT_SUCCESS);
          if (wait(NULL) != pid)
                  exit(EXIT_FAILURE);

          exit(EXIT_SUCCESS);
    }

  Since legacy clone() couldn't be extended this was not a problem so
  far and nobody really noticed or cared since nothing in the kernel
  ever bothered to look at the upper 32 bits.

  But once we introduced clone3() and expanded the flag argument in
  struct clone_args to 64 bit we opened this can of worms. With the
  first flag-based extension to clone3() making use of the upper 32 bits
  of the flag argument we've effectively made it possible for the legacy
  clone() syscall to reach clone3() only flags on accident. The sign
  extension scenario is just the odd corner-case that we needed to
  figure this out.

  The reason we just realized this now and not already when we
  introduced CLONE_CLEAR_SIGHAND was that CLONE_INTO_CGROUP assumes that
  a valid cgroup file descriptor has been given - whereas
  CLONE_CLEAR_SIGHAND doesn't need to verify anything. It just silently
  resets the signal handlers to SIG_DFL.

  So the sign extension (or the user accidently passing garbage for the
  upper 32 bits) caused the CLONE_INTO_CGROUP bit to be raised and the
  kernel to error out when it didn't find a valid cgroup file
  descriptor.

  Note, I'm also capping kernel_thread()'s flag argument mainly because
  none of the new features make sense for kernel_thread() and we
  shouldn't risk them being accidently activated however unlikely. If we
  wanted to, we could even make kernel_thread() yell when an unknown
  flag has been set which it doesn't do right now. But it's not worth
  risking this in a bugfix imho"

* tag 'for-linus-2020-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  fork: prevent accidental access to clone3 features
2020-05-14 11:52:28 -07:00
Linus Torvalds
f44d5c4890 Various tracing fixes:
- Fix a crash when having function tracing and function stack tracing on
    the command line. The ftrace trampolines are created as executable and
    read only. But the stack tracer tries to modify them with text_poke()
    which expects all kernel text to still be writable at boot.
    Keep the trampolines writable at boot, and convert them to read-only
    with the rest of the kernel.
 
  - A selftest was triggering in the ring buffer iterator code, that
    is no longer valid with the update of keeping the ring buffer
    writable while a iterator is reading. Just bail after three failed
    attempts to get an event and remove the warning and disabling of the
    ring buffer.
 
  - While modifying the ring buffer code, decided to remove all the
    unnecessary BUG() calls.
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Merge tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull more tracing fixes from Steven Rostedt:
 "Various tracing fixes:

   - Fix a crash when having function tracing and function stack tracing
     on the command line.

     The ftrace trampolines are created as executable and read only. But
     the stack tracer tries to modify them with text_poke() which
     expects all kernel text to still be writable at boot. Keep the
     trampolines writable at boot, and convert them to read-only with
     the rest of the kernel.

   - A selftest was triggering in the ring buffer iterator code, that is
     no longer valid with the update of keeping the ring buffer writable
     while a iterator is reading.

     Just bail after three failed attempts to get an event and remove
     the warning and disabling of the ring buffer.

   - While modifying the ring buffer code, decided to remove all the
     unnecessary BUG() calls"

* tag 'trace-v5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Remove all BUG() calls
  ring-buffer: Don't deactivate the ring buffer on failed iterator reads
  x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up
2020-05-14 11:46:52 -07:00
Steven Rostedt (VMware)
da4d401a6b ring-buffer: Remove all BUG() calls
There's a lot of checks to make sure the ring buffer is working, and if an
anomaly is detected, it safely shuts itself down. But there's a few cases
that it will call BUG(), which defeats the point of being safe (it crashes
the kernel when an anomaly is found!). There's no reason for them. Switch
them all to either WARN_ON_ONCE() (when no ring buffer descriptor is present),
or to RB_WARN_ON() (when a ring buffer descriptor is present).

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-14 08:51:02 -04:00
Steven Rostedt (VMware)
3d2353de81 ring-buffer: Don't deactivate the ring buffer on failed iterator reads
If the function tracer is running and the trace file is read (which uses the
ring buffer iterator), the iterator can get in sync with the writes, and
caues it to fail to find a page with content it can read three times. This
causes a warning and deactivation of the ring buffer code.

Looking at the other cases of failure to get an event, it appears that
there's a chance that the writer could cause them too. Since the iterator is
a "best effort" to read the ring buffer if there's an active writer (the
consumer reader is made for this case "see trace_pipe"), if it fails to get
an event after three tries, simply give up and return NULL. Don't warn, nor
disable the ring buffer on this failure.

Link: https://lore.kernel.org/r/20200429090508.GG5770@shao2-debian

Reported-by: kernel test robot <lkp@intel.com>
Fixes: ff84c50cfb ("ring-buffer: Do not die if rb_iter_peek() fails more than thrice")
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-14 08:50:51 -04:00
Yonghong Song
3c32cc1bce bpf: Enable bpf_iter targets registering ctx argument types
Commit b121b341e5 ("bpf: Add PTR_TO_BTF_ID_OR_NULL
support") adds a field btf_id_or_null_non0_off to
bpf_prog->aux structure to indicate that the
first ctx argument is PTR_TO_BTF_ID reg_type and
all others are PTR_TO_BTF_ID_OR_NULL.
This approach does not really scale if we have
other different reg types in the future, e.g.,
a pointer to a buffer.

This patch enables bpf_iter targets registering ctx argument
reg types which may be different from the default one.
For example, for pointers to structures, the default reg_type
is PTR_TO_BTF_ID for tracing program. The target can register
a particular pointer type as PTR_TO_BTF_ID_OR_NULL which can
be used by the verifier to enforce accesses.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180221.2949882-1-yhs@fb.com
2020-05-13 12:30:50 -07:00
Yonghong Song
ab2ee4fcb9 bpf: Change func bpf_iter_unreg_target() signature
Change func bpf_iter_unreg_target() parameter from target
name to target reg_info, similar to bpf_iter_reg_target().

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180220.2949737-1-yhs@fb.com
2020-05-13 12:30:50 -07:00
Yonghong Song
15172a46fa bpf: net: Refactor bpf_iter target registration
Currently bpf_iter_reg_target takes parameters from target
and allocates memory to save them. This is really not
necessary, esp. in the future we may grow information
passed from targets to bpf_iter manager.

The patch refactors the code so target reg_info
becomes static and bpf_iter manager can just take
a reference to it.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200513180219.2949605-1-yhs@fb.com
2020-05-13 12:30:50 -07:00
Yonghong Song
2e3ed68bfc bpf: Add comments to interpret bpf_prog return values
Add a short comment in bpf_iter_run_prog() function to
explain how bpf_prog return value is converted to
seq_ops->show() return value:
  bpf_prog return           seq_ops()->show() return
     0                         0
     1                         -EAGAIN

When show() return value is -EAGAIN, the current
bpf_seq_read() will end. If the current seq_file buffer
is empty, -EAGAIN will return to user space. Otherwise,
the buffer will be copied to user space.
In both cases, the next bpf_seq_read() call will
try to show the same object which returned -EAGAIN
previously.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180218.2949517-1-yhs@fb.com
2020-05-13 12:30:50 -07:00
Davidlohr Bueso
9d9a6ebfea rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken
Propagating the return value of wake_up_process() back to the caller
can come in handy for future users, such as for statistics or
accounting purposes.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-3-dave@stgolabs.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:52 -04:00
Davidlohr Bueso
c9d64a1b2d rcuwait: Fix stale wake call name in comment
The 'trywake' name was renamed to simply 'wake', update the comment.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Message-Id: <20200424054837.5138-2-dave@stgolabs.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-05-13 12:14:51 -04:00
Christian Brauner
303cc571d1
nsproxy: attach to namespaces via pidfds
For quite a while we have been thinking about using pidfds to attach to
namespaces. This patchset has existed for about a year already but we've
wanted to wait to see how the general api would be received and adopted.
Now that more and more programs in userspace have started using pidfds
for process management it's time to send this one out.

This patch makes it possible to use pidfds to attach to the namespaces
of another process, i.e. they can be passed as the first argument to the
setns() syscall. When only a single namespace type is specified the
semantics are equivalent to passing an nsfd. That means
setns(nsfd, CLONE_NEWNET) equals setns(pidfd, CLONE_NEWNET). However,
when a pidfd is passed, multiple namespace flags can be specified in the
second setns() argument and setns() will attach the caller to all the
specified namespaces all at once or to none of them. Specifying 0 is not
valid together with a pidfd.

Here are just two obvious examples:
setns(pidfd, CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWNET);
setns(pidfd, CLONE_NEWUSER);
Allowing to also attach subsets of namespaces supports various use-cases
where callers setns to a subset of namespaces to retain privilege, perform
an action and then re-attach another subset of namespaces.

If the need arises, as Eric suggested, we can extend this patchset to
assume even more context than just attaching all namespaces. His suggestion
specifically was about assuming the process' root directory when
setns(pidfd, 0) or setns(pidfd, SETNS_PIDFD) is specified. For now, just
keep it flexible in terms of supporting subsets of namespaces but let's
wait until we have users asking for even more context to be assumed. At
that point we can add an extension.

The obvious example where this is useful is a standard container
manager interacting with a running container: pushing and pulling files
or directories, injecting mounts, attaching/execing any kind of process,
managing network devices all these operations require attaching to all
or at least multiple namespaces at the same time. Given that nowadays
most containers are spawned with all namespaces enabled we're currently
looking at at least 14 syscalls, 7 to open the /proc/<pid>/ns/<ns>
nsfds, another 7 to actually perform the namespace switch. With time
namespaces we're looking at about 16 syscalls.
(We could amortize the first 7 or 8 syscalls for opening the nsfds by
 stashing them in each container's monitor process but that would mean
 we need to send around those file descriptors through unix sockets
 everytime we want to interact with the container or keep on-disk
 state. Even in scenarios where a caller wants to join a particular
 namespace in a particular order callers still profit from batching
 other namespaces. That mostly applies to the user namespace but
 all container runtimes I found join the user namespace first no matter
 if it privileges or deprivileges the container similar to how unshare
 behaves.)
With pidfds this becomes a single syscall no matter how many namespaces
are supposed to be attached to.

A decently designed, large-scale container manager usually isn't the
parent of any of the containers it spawns so the containers don't die
when it crashes or needs to update or reinitialize. This means that
for the manager to interact with containers through pids is inherently
racy especially on systems where the maximum pid number is not
significicantly bumped. This is even more problematic since we often spawn
and manage thousands or ten-thousands of containers. Interacting with a
container through a pid thus can become risky quite quickly. Especially
since we allow for an administrator to enable advanced features such as
syscall interception where we're performing syscalls in lieu of the
container. In all of those cases we use pidfds if they are available and
we pass them around as stable references. Using them to setns() to the
target process' namespaces is as reliable as using nsfds. Either the
target process is already dead and we get ESRCH or we manage to attach
to its namespaces but we can't accidently attach to another process'
namespaces. So pidfds lend themselves to be used with this api.
The other main advantage is that with this change the pidfd becomes the
only relevant token for most container interactions and it's the only
token we need to create and send around.

Apart from significiantly reducing the number of syscalls from double
digit to single digit which is a decent reason post-spectre/meltdown
this also allows to switch to a set of namespaces atomically, i.e.
either attaching to all the specified namespaces succeeds or we fail. If
we fail we haven't changed a single namespace. There are currently three
namespaces that can fail (other than for ENOMEM which really is not
very interesting since we then have other problems anyway) for
non-trivial reasons, user, mount, and pid namespaces. We can fail to
attach to a pid namespace if it is not our current active pid namespace
or a descendant of it. We can fail to attach to a user namespace because
we are multi-threaded or because our current mount namespace shares
filesystem state with other tasks, or because we're trying to setns()
to the same user namespace, i.e. the target task has the same user
namespace as we do. We can fail to attach to a mount namespace because
it shares filesystem state with other tasks or because we fail to lookup
the new root for the new mount namespace. In most non-pathological
scenarios these issues can be somewhat mitigated. But there are cases where
we're half-attached to some namespace and failing to attach to another one.
I've talked about some of these problem during the hallway track (something
only the pre-COVID-19 generation will remember) of Plumbers in Los Angeles
in 2018(?). Even if all these issues could be avoided with super careful
userspace coding it would be nicer to have this done in-kernel. Pidfds seem
to lend themselves nicely for this.

The other neat thing about this is that setns() becomes an actual
counterpart to the namespace bits of unshare().

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jann Horn <jannh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20200505140432.181565-3-christian.brauner@ubuntu.com
2020-05-13 11:41:22 +02:00
Steven Rostedt (VMware)
59566b0b62 x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up
Booting one of my machines, it triggered the following crash:

 Kernel/User page tables isolation: enabled
 ftrace: allocating 36577 entries in 143 pages
 Starting tracer 'function'
 BUG: unable to handle page fault for address: ffffffffa000005c
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0003) - permissions violation
 PGD 2014067 P4D 2014067 PUD 2015063 PMD 7b253067 PTE 7b252061
 Oops: 0003 [#1] PREEMPT SMP PTI
 CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.0-test+ #24
 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
 RIP: 0010:text_poke_early+0x4a/0x58
 Code: 34 24 48 89 54 24 08 e8 bf 72 0b 00 48 8b 34 24 48 8b 4c 24 08 84 c0 74 0b 48 89 df f3 a4 48 83 c4 10 5b c3 9c 58 fa 48 89 df <f3> a4 50 9d 48 83 c4 10 5b e9 d6 f9 ff ff
0 41 57 49
 RSP: 0000:ffffffff82003d38 EFLAGS: 00010046
 RAX: 0000000000000046 RBX: ffffffffa000005c RCX: 0000000000000005
 RDX: 0000000000000005 RSI: ffffffff825b9a90 RDI: ffffffffa000005c
 RBP: ffffffffa000005c R08: 0000000000000000 R09: ffffffff8206e6e0
 R10: ffff88807b01f4c0 R11: ffffffff8176c106 R12: ffffffff8206e6e0
 R13: ffffffff824f2440 R14: 0000000000000000 R15: ffffffff8206eac0
 FS:  0000000000000000(0000) GS:ffff88807d400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffffffffa000005c CR3: 0000000002012000 CR4: 00000000000006b0
 Call Trace:
  text_poke_bp+0x27/0x64
  ? mutex_lock+0x36/0x5d
  arch_ftrace_update_trampoline+0x287/0x2d5
  ? ftrace_replace_code+0x14b/0x160
  ? ftrace_update_ftrace_func+0x65/0x6c
  __register_ftrace_function+0x6d/0x81
  ftrace_startup+0x23/0xc1
  register_ftrace_function+0x20/0x37
  func_set_flag+0x59/0x77
  __set_tracer_option.isra.19+0x20/0x3e
  trace_set_options+0xd6/0x13e
  apply_trace_boot_options+0x44/0x6d
  register_tracer+0x19e/0x1ac
  early_trace_init+0x21b/0x2c9
  start_kernel+0x241/0x518
  ? load_ucode_intel_bsp+0x21/0x52
  secondary_startup_64+0xa4/0xb0

I was able to trigger it on other machines, when I added to the kernel
command line of both "ftrace=function" and "trace_options=func_stack_trace".

The cause is the "ftrace=function" would register the function tracer
and create a trampoline, and it will set it as executable and
read-only. Then the "trace_options=func_stack_trace" would then update
the same trampoline to include the stack tracer version of the function
tracer. But since the trampoline already exists, it updates it with
text_poke_bp(). The problem is that text_poke_bp() called while
system_state == SYSTEM_BOOTING, it will simply do a memcpy() and not
the page mapping, as it would think that the text is still read-write.
But in this case it is not, and we take a fault and crash.

Instead, lets keep the ftrace trampolines read-write during boot up,
and then when the kernel executable text is set to read-only, the
ftrace trampolines get set to read-only as well.

Link: https://lkml.kernel.org/r/20200430202147.4dc6e2de@oasis.local.home

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable@vger.kernel.org
Fixes: 768ae4406a ("x86/ftrace: Use text_poke()")
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-12 18:24:34 -04:00
Linus Torvalds
24085f70a6 Tracing fixes to previous fixes:
Unfortunately, the last set of fixes introduced some minor bugs:
 
  - The bootconfig apply_xbc() leak fix caused the application to return
    a positive number on success, when it should have returned zero.
 
  - The preempt_irq_delay_thread fix to make the creation code
    wait for the kthread to finish to prevent it from executing after
    module unload, can now cause the kthread to exit before it even
    executes (preventing it to run its tests).
 
  - The fix to the bootconfig that fixed the initrd to remove the
    bootconfig from causing the kernel to panic, now prints a warning
    that the bootconfig is not found, even when bootconfig is not
    on the command line.
 -----BEGIN PGP SIGNATURE-----
 
 iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCXrq2ehQccm9zdGVkdEBn
 b29kbWlzLm9yZwAKCRAp5XQQmuv6qrdjAQDGNaJa7Ft13KTDTNTioKmOorOi38vF
 ava4E3uBHl3StQD/anJmVq7Kk4WJFKGYemV6usbjDqy510PCFu/VQ1AbGQc=
 =hJvk
 -----END PGP SIGNATURE-----

Merge tag 'trace-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Fixes to previous fixes.

  Unfortunately, the last set of fixes introduced some minor bugs:

   - The bootconfig apply_xbc() leak fix caused the application to
     return a positive number on success, when it should have returned
     zero.

   - The preempt_irq_delay_thread fix to make the creation code wait for
     the kthread to finish to prevent it from executing after module
     unload, can now cause the kthread to exit before it even executes
     (preventing it to run its tests).

   - The fix to the bootconfig that fixed the initrd to remove the
     bootconfig from causing the kernel to panic, now prints a warning
     that the bootconfig is not found, even when bootconfig is not on
     the command line"

* tag 'trace-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  bootconfig: Fix to prevent warning message if no bootconfig option
  tracing: Wait for preempt irq delay thread to execute
  tools/bootconfig: Fix apply_xbc() to return zero on success
2020-05-12 11:06:26 -07:00
Masami Hiramatsu
16db6264c9 kprobes: Support NOKPROBE_SYMBOL() in modules
Support NOKPROBE_SYMBOL() in modules. NOKPROBE_SYMBOL() records only symbol
address in "_kprobe_blacklist" section in the module.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.771170126@linutronix.de
2020-05-12 17:15:32 +02:00
Masami Hiramatsu
1e6769b0ae kprobes: Support __kprobes blacklist in modules
Support __kprobes attribute for blacklist functions in modules.  The
__kprobes attribute functions are stored in .kprobes.text section.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.678201813@linutronix.de
2020-05-12 17:15:32 +02:00
Masami Hiramatsu
4fdd88877e kprobes: Lock kprobe_mutex while showing kprobe_blacklist
Lock kprobe_mutex while showing kprobe_blacklist to prevent updating the
kprobe_blacklist.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.571125195@linutronix.de
2020-05-12 17:15:31 +02:00
Thomas Gleixner
2a0a24ebb4 sched: Make scheduler_ipi inline
Now that the scheduler IPI is trivial and simple again there is no point to
have the little function out of line. This simplifies the effort of
constraining the instrumentation nicely.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134058.453581595@linutronix.de
2020-05-12 17:10:49 +02:00
Peter Zijlstra (Intel)
90b5363acd sched: Clean up scheduler_ipi()
The scheduler IPI has grown weird and wonderful over the years, time
for spring cleaning.

Move all the non-trivial stuff out of it and into a regular smp function
call IPI. This then reduces the schedule_ipi() to most of it's former NOP
glory and ensures to keep the interrupt vector lean and mean.

Aside of that avoiding the full irq_enter() in the x86 IPI implementation
is incorrect as scheduler_ipi() can be instrumented. To work around that
scheduler_ipi() had an irq_enter/exit() hack when heavy work was
pending. This is gone now.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505134058.361859938@linutronix.de
2020-05-12 17:10:48 +02:00
Steven Rostedt (VMware)
8b1fac2e73 tracing: Wait for preempt irq delay thread to execute
A bug report was posted that running the preempt irq delay module on a slow
machine, and removing it quickly could lead to the thread created by the
modlue to execute after the module is removed, and this could cause the
kernel to crash. The fix for this was to call kthread_stop() after creating
the thread to make sure it finishes before allowing the module to be
removed.

Now this caused the opposite problem on fast machines. What now happens is
the kthread_stop() can cause the kthread never to execute and the test never
to run. To fix this, add a completion and wait for the kthread to execute,
then wait for it to end.

This issue caused the ftracetest selftests to fail on the preemptirq tests.

Link: https://lore.kernel.org/r/20200510114210.15d9e4af@oasis.local.home

Cc: stable@vger.kernel.org
Fixes: d16a8c3107 ("tracing: Wait for preempt irq delay thread to finish")
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-11 17:00:34 -04:00
Gustavo A. R. Silva
385bbf7b11 bpf, libbpf: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200507185057.GA13981@embeddedor
2020-05-11 16:56:47 +02:00
Dan Carpenter
b92b36eadf workqueue: Fix an use after free in init_rescuer()
We need to preserve error code before freeing "rescuer".

Fixes: f187b6974f ("workqueue: Use IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-11 10:25:42 -04:00
Samuel Zou
a4ae16f65c livepatch: Make klp_apply_object_relocs static
Fix the following sparse warning:

kernel/livepatch/core.c:748:5: warning: symbol 'klp_apply_object_relocs' was
not declared.

The klp_apply_object_relocs() has only one call site within core.c;
it should be static

Fixes: 7c8e2bdd5f ("livepatch: Apply vmlinux-specific KLP relocations early")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Samuel Zou <zou_wei@huawei.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-11 00:31:38 +02:00
Xiaoming Ni
b6522fa409 parisc: add sysctl file interface panic_on_stackoverflow
The variable sysctl_panic_on_stackoverflow is used in
arch/parisc/kernel/irq.c and arch/x86/kernel/irq_32.c, but the sysctl file
interface panic_on_stackoverflow only exists on x86.

Add sysctl file interface panic_on_stackoverflow for parisc

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
2020-05-10 22:47:35 +02:00
Yonghong Song
9c5f8a1008 bpf: Support variable length array in tracing programs
In /proc/net/ipv6_route, we have
  struct fib6_info {
    struct fib6_table *fib6_table;
    ...
    struct fib6_nh fib6_nh[0];
  }
  struct fib6_nh {
    struct fib_nh_common nh_common;
    struct rt6_info **rt6i_pcpu;
    struct rt6_exception_bucket *rt6i_exception_bucket;
  };
  struct fib_nh_common {
    ...
    u8 nhc_gw_family;
    ...
  }

The access:
  struct fib6_nh *fib6_nh = &rt->fib6_nh;
  ... fib6_nh->nh_common.nhc_gw_family ...

This patch ensures such an access is handled properly.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175916.2476853-1-yhs@fb.com
2020-05-09 17:05:27 -07:00
Yonghong Song
1d68f22b3d bpf: Handle spilled PTR_TO_BTF_ID properly when checking stack_boundary
This specifically to handle the case like below:
   // ptr below is a socket ptr identified by PTR_TO_BTF_ID
   u64 param[2] = { ptr, val };
   bpf_seq_printf(seq, fmt, sizeof(fmt), param, sizeof(param));

In this case, the 16 bytes stack for "param" contains:
   8 bytes for ptr with spilled PTR_TO_BTF_ID
   8 bytes for val as STACK_MISC

The current verifier will complain the ptr should not be visible
to the helper.
   ...
   16: (7b) *(u64 *)(r10 -64) = r2
   18: (7b) *(u64 *)(r10 -56) = r1
   19: (bf) r4 = r10
   ;
   20: (07) r4 += -64
   ; BPF_SEQ_PRINTF(seq, fmt1, (long)s, s->sk_protocol);
   21: (bf) r1 = r6
   22: (18) r2 = 0xffffa8d00018605a
   24: (b4) w3 = 10
   25: (b4) w5 = 16
   26: (85) call bpf_seq_printf#125
    R0=inv(id=0) R1_w=ptr_seq_file(id=0,off=0,imm=0)
    R2_w=map_value(id=0,off=90,ks=4,vs=144,imm=0) R3_w=inv10
    R4_w=fp-64 R5_w=inv16 R6=ptr_seq_file(id=0,off=0,imm=0)
    R7=ptr_netlink_sock(id=0,off=0,imm=0) R10=fp0 fp-56_w=mmmmmmmm
    fp-64_w=ptr_
   last_idx 26 first_idx 13
   regs=8 stack=0 before 25: (b4) w5 = 16
   regs=8 stack=0 before 24: (b4) w3 = 10
   invalid indirect read from stack off -64+0 size 16

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175915.2476783-1-yhs@fb.com
2020-05-09 17:05:27 -07:00
Yonghong Song
492e639f0c bpf: Add bpf_seq_printf and bpf_seq_write helpers
Two helpers bpf_seq_printf and bpf_seq_write, are added for
writing data to the seq_file buffer.

bpf_seq_printf supports common format string flag/width/type
fields so at least I can get identical results for
netlink and ipv6_route targets.

For bpf_seq_printf and bpf_seq_write, return value -EOVERFLOW
specifically indicates a write failure due to overflow, which
means the object will be repeated in the next bpf invocation
if object collection stays the same. Note that if the object
collection is changed, depending how collection traversal is
done, even if the object still in the collection, it may not
be visited.

For bpf_seq_printf, format %s, %p{i,I}{4,6} needs to
read kernel memory. Reading kernel memory may fail in
the following two cases:
  - invalid kernel address, or
  - valid kernel address but requiring a major fault
If reading kernel memory failed, the %s string will be
an empty string and %p{i,I}{4,6} will be all 0.
Not returning error to bpf program is consistent with
what bpf_trace_printk() does for now.

bpf_seq_printf may return -EBUSY meaning that internal percpu
buffer for memory copy of strings or other pointees is
not available. Bpf program can return 1 to indicate it
wants the same object to be repeated. Right now, this should not
happen on no-RT kernels since migrate_disable(), which guards
bpf prog call, calls preempt_disable().

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175914.2476661-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
b121b341e5 bpf: Add PTR_TO_BTF_ID_OR_NULL support
Add bpf_reg_type PTR_TO_BTF_ID_OR_NULL support.
For tracing/iter program, the bpf program context
definition, e.g., for previous bpf_map target, looks like
  struct bpf_iter__bpf_map {
    struct bpf_iter_meta *meta;
    struct bpf_map *map;
  };

The kernel guarantees that meta is not NULL, but
map pointer maybe NULL. The NULL map indicates that all
objects have been traversed, so bpf program can take
proper action, e.g., do final aggregation and/or send
final report to user space.

Add btf_id_or_null_non0_off to prog->aux structure, to
indicate that if the context access offset is not 0,
set to PTR_TO_BTF_ID_OR_NULL instead of PTR_TO_BTF_ID.
This bit is set for tracing/iter program.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175912.2476576-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
eaaacd2391 bpf: Add task and task/file iterator targets
Only the tasks belonging to "current" pid namespace
are enumerated.

For task/file target, the bpf program will have access to
  struct task_struct *task
  u32 fd
  struct file *file
where fd/file is an open file for the task.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175911.2476407-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
6086d29def bpf: Add bpf_map iterator
Implement seq_file operations to traverse all bpf_maps.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175909.2476096-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
e5158d987b bpf: Implement common macros/helpers for target iterators
Macro DEFINE_BPF_ITER_FUNC is implemented so target
can define an init function to capture the BTF type
which represents the target.

The bpf_iter_meta is a structure holding meta data, common
to all targets in the bpf program.

Additional marker functions are called before or after
bpf_seq_read() show()/next()/stop() callback functions
to help calculate precise seq_num and whether call bpf_prog
inside stop().

Two functions, bpf_iter_get_info() and bpf_iter_run_prog(),
are implemented so target can get needed information from
bpf_iter infrastructure and can run the program.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175907.2475956-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
367ec3e483 bpf: Create file bpf iterator
To produce a file bpf iterator, the fd must be
corresponding to a link_fd assocciated with a
trace/iter program. When the pinned file is
opened, a seq_file will be generated.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175906.2475893-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
ac51d99bf8 bpf: Create anonymous bpf iterator
A new bpf command BPF_ITER_CREATE is added.

The anonymous bpf iterator is seq_file based.
The seq_file private data are referenced by targets.
The bpf_iter infrastructure allocated additional space
at seq_file->private before the space used by targets
to store some meta data, e.g.,
  prog:       prog to run
  session_id: an unique id for each opened seq_file
  seq_num:    how many times bpf programs are queried in this session
  done_stop:  an internal state to decide whether bpf program
              should be called in seq_ops->stop() or not

The seq_num will start from 0 for valid objects.
The bpf program may see the same seq_num more than once if
 - seq_file buffer overflow happens and the same object
   is retried by bpf_seq_read(), or
 - the bpf program explicitly requests a retry of the
   same object

Since module is not supported for bpf_iter, all target
registeration happens at __init time, so there is no
need to change bpf_iter_unreg_target() as it is used
mostly in error path of the init function at which time
no bpf iterators have been created yet.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175905.2475770-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
fd4f12bc38 bpf: Implement bpf_seq_read() for bpf iterator
bpf iterator uses seq_file to provide a lossless
way to transfer data to user space. But we want to call
bpf program after all objects have been traversed, and
bpf program may write additional data to the
seq_file buffer. The current seq_read() does not work
for this use case.

Besides allowing stop() function to write to the buffer,
the bpf_seq_read() also fixed the buffer size to one page.
If any single call of show() or stop() will emit data
more than one page to cause overflow, -E2BIG error code
will be returned to user space.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175904.2475468-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
2057c92bc9 bpf: Support bpf tracing/iter programs for BPF_LINK_UPDATE
Added BPF_LINK_UPDATE support for tracing/iter programs.
This way, a file based bpf iterator, which holds a reference
to the link, can have its bpf program updated without
creating new files.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175902.2475262-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
de4e05cac4 bpf: Support bpf tracing/iter programs for BPF_LINK_CREATE
Given a bpf program, the step to create an anonymous bpf iterator is:
  - create a bpf_iter_link, which combines bpf program and the target.
    In the future, there could be more information recorded in the link.
    A link_fd will be returned to the user space.
  - create an anonymous bpf iterator with the given link_fd.

The bpf_iter_link can be pinned to bpffs mount file system to
create a file based bpf iterator as well.

The benefit to use of bpf_iter_link:
  - using bpf link simplifies design and implementation as bpf link
    is used for other tracing bpf programs.
  - for file based bpf iterator, bpf_iter_link provides a standard
    way to replace underlying bpf programs.
  - for both anonymous and free based iterators, bpf link query
    capability can be leveraged.

The patch added support of tracing/iter programs for BPF_LINK_CREATE.
A new link type BPF_LINK_TYPE_ITER is added to facilitate link
querying. Currently, only prog_id is needed, so there is no
additional in-kernel show_fdinfo() and fill_link_info() hook
is needed for BPF_LINK_TYPE_ITER link.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175901.2475084-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
15d83c4d7c bpf: Allow loading of a bpf_iter program
A bpf_iter program is a tracing program with attach type
BPF_TRACE_ITER. The load attribute
  attach_btf_id
is used by the verifier against a particular kernel function,
which represents a target, e.g., __bpf_iter__bpf_map
for target bpf_map which is implemented later.

The program return value must be 0 or 1 for now.
  0 : successful, except potential seq_file buffer overflow
      which is handled by seq_file reader.
  1 : request to restart the same object

In the future, other return values may be used for filtering or
teminating the iterator.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175900.2474947-1-yhs@fb.com
2020-05-09 17:05:26 -07:00
Yonghong Song
ae24345da5 bpf: Implement an interface to register bpf_iter targets
The target can call bpf_iter_reg_target() to register itself.
The needed information:
  target:           target name
  seq_ops:          the seq_file operations for the target
  init_seq_private  target callback to initialize seq_priv during file open
  fini_seq_private  target callback to clean up seq_priv during file release
  seq_priv_size:    the private_data size needed by the seq_file
                    operations

The target name represents a target which provides a seq_ops
for iterating objects.

The target can provide two callback functions, init_seq_private
and fini_seq_private, called during file open/release time.
For example, /proc/net/{tcp6, ipv6_route, netlink, ...}, net
name space needs to be setup properly during file open and
released properly during file release.

Function bpf_iter_unreg_target() is also implemented to unregister
a particular target.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175859.2474669-1-yhs@fb.com
2020-05-09 17:05:25 -07:00
Linus Torvalds
78a5255ffb Stop the ad-hoc games with -Wno-maybe-initialized
We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-09 13:57:10 -07:00
Christian Brauner
f2a8d52e0a
nsproxy: add struct nsset
Add a simple struct nsset. It holds all necessary pieces to switch to a new
set of namespaces without leaving a task in a half-switched state which we
will make use of in the next patch. This patch switches the existing setns
logic over without causing a change in setns() behavior. This brings
setns() closer to how unshare() works(). The prepare_ns() function is
responsible to prepare all necessary information. This has two reasons.
First it minimizes dependencies between individual namespaces, i.e. all
install handler can expect that all fields are properly initialized
independent in what order they are called in. Second, this makes the code
easier to maintain and easier to follow if it needs to be changed.

The prepare_ns() helper will only be switched over to use a flags argument
in the next patch. Here it will still use nstype as a simple integer
argument which was argued would be clearer. I'm not particularly
opinionated about this if it really helps or not. The struct nsset itself
already contains the flags field since its name already indicates that it
can contain information required by different namespaces. None of this
should have functional consequences.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jann Horn <jannh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Link: https://lore.kernel.org/r/20200505140432.181565-2-christian.brauner@ubuntu.com
2020-05-09 13:57:12 +02:00
Vincent Minet
db803036ad umh: fix memory leak on execve failure
If a UMH process created by fork_usermode_blob() fails to execute,
a pair of struct file allocated by umh_pipe_setup() will leak.

Under normal conditions, the caller (like bpfilter) needs to manage the
lifetime of the UMH and its two pipes. But when fork_usermode_blob()
fails, the caller doesn't really have a way to know what needs to be
done. It seems better to do the cleanup ourselves in this case.

Fixes: 449325b52b ("umh: introduce fork_usermode_blob() helper")
Signed-off-by: Vincent Minet <v.minet@criteo.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-05-08 19:06:55 -07:00
Jakub Kicinski
14d8f7486a Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2020-05-09

The following pull-request contains BPF updates for your *net* tree.

We've added 4 non-merge commits during the last 9 day(s) which contain
a total of 4 files changed, 11 insertions(+), 6 deletions(-).

The main changes are:

1) Fix msg_pop_data() helper incorrectly setting an sge length in some
   cases as well as fixing bpf_tcp_ingress() wrongly accounting bytes
   in sg.size, from John Fastabend.

2) Fix to return an -EFAULT error when copy_to_user() of the value
   fails in map_lookup_and_delete_elem(), from Wei Yongjun.

3) Fix sk_psock refcnt leak in tcp_bpf_recvmsg(), from Xiyu Yang.
====================

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-05-08 18:58:39 -07:00
J. Bruce Fields
52782c92ac kthread: save thread function
It's handy to keep the kthread_fn just as a unique cookie to identify
classes of kthreads.  E.g. if you can verify that a given task is
running your thread_fn, then you may know what sort of type kthread_data
points to.

We'll use this in nfsd to pass some information into the vfs.  Note it
will need kthread_data() exported too.

Original-patch-by: Tejun Heo <tj@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2020-05-08 21:23:10 -04:00
Linus Torvalds
c61529f6f5 Driver core fixes for 5.7-rc5
Here are a number of small driver core fixes for 5.7-rc5 to resolve a
 bunch of reported issues with the current tree.
 
 Biggest here are the reverts and patches from John Stultz to resolve a
 bunch of deferred probe regressions we have been seeing in 5.7-rc right
 now.
 
 Along with those are some other smaller fixes:
 	- coredump crash fix
 	- devlink fix for when permissive mode was enabled
 	- amba and platform device dma_parms fixes
 	- component error silenced for when deferred probe happens
 
 All of these have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are a number of small driver core fixes for 5.7-rc5 to resolve a
  bunch of reported issues with the current tree.

  Biggest here are the reverts and patches from John Stultz to resolve a
  bunch of deferred probe regressions we have been seeing in 5.7-rc
  right now.

  Along with those are some other smaller fixes:

   - coredump crash fix

   - devlink fix for when permissive mode was enabled

   - amba and platform device dma_parms fixes

   - component error silenced for when deferred probe happens

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  regulator: Revert "Use driver_deferred_probe_timeout for regulator_init_complete_work"
  driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires
  driver core: Use dev_warn() instead of dev_WARN() for deferred_probe_timeout warnings
  driver core: Revert default driver_deferred_probe_timeout value to 0
  component: Silence bind error on -EPROBE_DEFER
  driver core: Fix handling of fw_devlink=permissive
  coredump: fix crash when umh is disabled
  amba: Initialize dma_parms for amba devices
  driver core: platform: Initialize dma_parms for platform devices
2020-05-08 09:06:34 -07:00
Linus Torvalds
af38553c66 Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
 "14 fixes and one selftest to verify the ipc fixes herein"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: limit boost_watermark on small zones
  ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST
  mm/vmscan: remove unnecessary argument description of isolate_lru_pages()
  epoll: atomically remove wait entry on wake up
  kselftests: introduce new epoll60 testcase for catching lost wakeups
  percpu: make pcpu_alloc() aware of current gfp context
  mm/slub: fix incorrect interpretation of s->offset
  scripts/gdb: repair rb_first() and rb_last()
  eventpoll: fix missing wakeup for ovflist in ep_poll_callback
  arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory()
  scripts/decodecode: fix trapping instruction formatting
  kernel/kcov.c: fix typos in kcov_remote_start documentation
  mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous()
  mm, memcg: fix error return value of mem_cgroup_css_alloc()
  ipc/mqueue.c: change __do_notify() to bypass check_kill_permission()
2020-05-08 08:41:09 -07:00
Christian Brauner
3f2c788a13
fork: prevent accidental access to clone3 features
Jan reported an issue where an interaction between sign-extending clone's
flag argument on ppc64le and the new CLONE_INTO_CGROUP feature causes
clone() to consistently fail with EBADF.

The whole story is a little longer. The legacy clone() syscall is odd in a
bunch of ways and here two things interact. First, legacy clone's flag
argument is word-size dependent, i.e. it's an unsigned long whereas most
system calls with flag arguments use int or unsigned int. Second, legacy
clone() ignores unknown and deprecated flags. The two of them taken
together means that users on 64bit systems can pass garbage for the upper
32bit of the clone() syscall since forever and things would just work fine.
Just try this on a 64bit kernel prior to v5.7-rc1 where this will succeed
and on v5.7-rc1 where this will fail with EBADF:

int main(int argc, char *argv[])
{
        pid_t pid;

        /* Note that legacy clone() has different argument ordering on
         * different architectures so this won't work everywhere.
         *
         * Only set the upper 32 bits.
         */
        pid = syscall(__NR_clone, 0xffffffff00000000 | SIGCHLD,
                      NULL, NULL, NULL, NULL);
        if (pid < 0)
                exit(EXIT_FAILURE);
        if (pid == 0)
                exit(EXIT_SUCCESS);
        if (wait(NULL) != pid)
                exit(EXIT_FAILURE);

        exit(EXIT_SUCCESS);
}

Since legacy clone() couldn't be extended this was not a problem so far and
nobody really noticed or cared since nothing in the kernel ever bothered to
look at the upper 32 bits.

But once we introduced clone3() and expanded the flag argument in struct
clone_args to 64 bit we opened this can of worms. With the first flag-based
extension to clone3() making use of the upper 32 bits of the flag argument
we've effectively made it possible for the legacy clone() syscall to reach
clone3() only flags. The sign extension scenario is just the odd
corner-case that we needed to figure this out.

The reason we just realized this now and not already when we introduced
CLONE_CLEAR_SIGHAND was that CLONE_INTO_CGROUP assumes that a valid cgroup
file descriptor has been given. So the sign extension (or the user
accidently passing garbage for the upper 32 bits) caused the
CLONE_INTO_CGROUP bit to be raised and the kernel to error out when it
didn't find a valid cgroup file descriptor.

Let's fix this by always capping the upper 32 bits for all codepaths that
are not aware of clone3() features. This ensures that we can't reach
clone3() only features by accident via legacy clone as with the sign
extension case and also that legacy clone() works exactly like before, i.e.
ignoring any unknown flags.  This solution risks no regressions and is also
pretty clean.

Fixes: 7f192e3cd3 ("fork: add clone3")
Fixes: ef2c41cf38 ("clone3: allow spawning processes into cgroups")
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Florian Weimer <fw@deneb.enyo.de>
Cc: libc-alpha@sourceware.org
Cc: stable@vger.kernel.org # 5.3+
Link: https://sourceware.org/pipermail/libc-alpha/2020-May/113596.html
Link: https://lore.kernel.org/r/20200507103214.77218-1-christian.brauner@ubuntu.com
2020-05-08 17:31:50 +02:00
Thomas Gleixner
97a9474aeb Merge branch 'kcsan-for-tip' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/kcsan
Pull KCSAN updates from Paul McKenney.
2020-05-08 14:58:28 +02:00
Eric Biggers
6b0b0fa2bc crypto: lib/sha1 - rename "sha" to "sha1"
The library implementation of the SHA-1 compression function is
confusingly called just "sha_transform()".  Alongside it are some "SHA_"
constants and "sha_init()".  Presumably these are left over from a time
when SHA just meant SHA-1.  But now there are also SHA-2 and SHA-3, and
moreover SHA-1 is now considered insecure and thus shouldn't be used.

Therefore, rename these functions and constants to make it very clear
that they are for SHA-1.  Also add a comment to make it clear that these
shouldn't be used.

For the extra-misleadingly named "SHA_MESSAGE_BYTES", rename it to
SHA1_BLOCK_SIZE and define it to just '64' rather than '(512/8)' so that
it matches the same definition in <crypto/sha.h>.  This prepares for
merging <linux/cryptohash.h> into <crypto/sha.h>.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-05-08 15:32:17 +10:00
Maciej Grochowski
324cfb1956 kernel/kcov.c: fix typos in kcov_remote_start documentation
Signed-off-by: Maciej Grochowski <maciej.grochowski@pm.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Link: http://lkml.kernel.org/r/20200420030259.31674-1-maciek.grochowski@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-07 19:27:20 -07:00
Linus Torvalds
192ffb7515 This includes the following tracing fixes:
- Fix bootconfig causing kernels to fail with CONFIG_BLK_DEV_RAM enabled
  - Fix allocation leaks in bootconfig tool
  - Fix a double initialization of a variable
  - Fix API bootconfig usage from kprobe boot time events
  - Reject NULL location for kprobes
  - Fix crash caused by preempt delay module not cleaning up kthread
    correctly
  - Add vmalloc_sync_mappings() to prevent x86_64 page faults from
    recursively faulting from tracing page faults
  - Fix comment in gpu/trace kerneldoc header
  - Fix documentation of how to create a trace event class
  - Make the local tracing_snapshot_instance_cond() function static
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Merge tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix bootconfig causing kernels to fail with CONFIG_BLK_DEV_RAM
   enabled

 - Fix allocation leaks in bootconfig tool

 - Fix a double initialization of a variable

 - Fix API bootconfig usage from kprobe boot time events

 - Reject NULL location for kprobes

 - Fix crash caused by preempt delay module not cleaning up kthread
   correctly

 - Add vmalloc_sync_mappings() to prevent x86_64 page faults from
   recursively faulting from tracing page faults

 - Fix comment in gpu/trace kerneldoc header

 - Fix documentation of how to create a trace event class

 - Make the local tracing_snapshot_instance_cond() function static

* tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tools/bootconfig: Fix resource leak in apply_xbc()
  tracing: Make tracing_snapshot_instance_cond() static
  tracing: Fix doc mistakes in trace sample
  gpu/trace: Minor comment updates for gpu_mem_total tracepoint
  tracing: Add a vmalloc_sync_mappings() for safe measure
  tracing: Wait for preempt irq delay thread to finish
  tracing/kprobes: Reject new event if loc is NULL
  tracing/boottime: Fix kprobe event API usage
  tracing/kprobes: Fix a double initialization typo
  bootconfig: Fix to remove bootconfig data from initrd while boot
2020-05-07 15:27:11 -07:00
Josh Poimboeuf
e6eff4376e module: Make module_enable_ro() static again
Now that module_enable_ro() has no more external users, make it static
again.

Suggested-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:43 +02:00
Josh Poimboeuf
5b384f9335 x86/module: Use text_mutex in apply_relocate_add()
Now that the livepatch code no longer needs the text_mutex for changing
module permissions, move its usage down to apply_relocate_add().

Note the s390 version of apply_relocate_add() doesn't need to use the
text_mutex because it already uses s390_kernel_write_lock, which
accomplishes the same task.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:43 +02:00
Josh Poimboeuf
0d9fbf78fe module: Remove module_disable_ro()
module_disable_ro() has no more users.  Remove it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:43 +02:00
Josh Poimboeuf
d556e1be33 livepatch: Remove module_disable_ro() usage
With arch_klp_init_object_loaded() gone, and apply_relocate_add() now
using text_poke(), livepatch no longer needs to use module_disable_ro().

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:43 +02:00
Josh Poimboeuf
ca376a9374 livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols
Prevent module-specific KLP rela sections from referencing vmlinux
symbols.  This helps prevent ordering issues with module special section
initializations.  Presumably such symbols are exported and normal relas
can be used instead.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:42 +02:00
Peter Zijlstra
1d05334d28 livepatch: Remove .klp.arch
After the previous patch, vmlinux-specific KLP relocations are now
applied early during KLP module load.  This means that .klp.arch
sections are no longer needed for *vmlinux-specific* KLP relocations.

One might think they're still needed for *module-specific* KLP
relocations.  If a to-be-patched module is loaded *after* its
corresponding KLP module is loaded, any corresponding KLP relocations
will be delayed until the to-be-patched module is loaded.  If any
special sections (.parainstructions, for example) rely on those
relocations, their initializations (apply_paravirt) need to be done
afterwards.  Thus the apparent need for arch_klp_init_object_loaded()
and its corresponding .klp.arch sections -- it allows some of the
special section initializations to be done at a later time.

But... if you look closer, that dependency between the special sections
and the module-specific KLP relocations doesn't actually exist in
reality.  Looking at the contents of the .altinstructions and
.parainstructions sections, there's not a realistic scenario in which a
KLP module's .altinstructions or .parainstructions section needs to
access a symbol in a to-be-patched module.  It might need to access a
local symbol or even a vmlinux symbol; but not another module's symbol.
When a special section needs to reference a local or vmlinux symbol, a
normal rela can be used instead of a KLP rela.

Since the special section initializations don't actually have any real
dependency on module-specific KLP relocations, .klp.arch and
arch_klp_init_object_loaded() no longer have a reason to exist.  So
remove them.

As Peter said much more succinctly:

  So the reason for .klp.arch was that .klp.rela.* stuff would overwrite
  paravirt instructions. If that happens you're doing it wrong. Those
  RELAs are core kernel, not module, and thus should've happened in
  .rela.* sections at patch-module loading time.

  Reverting this removes the two apply_{paravirt,alternatives}() calls
  from the late patching path, and means we don't have to worry about
  them when removing module_disable_ro().

[ jpoimboe: Rewrote patch description.  Tweaked klp_init_object_loaded()
	    error path. ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:42 +02:00
Josh Poimboeuf
7c8e2bdd5f livepatch: Apply vmlinux-specific KLP relocations early
KLP relocations are livepatch-specific relocations which are applied to
a KLP module's text or data.  They exist for two reasons:

  1) Unexported symbols: replacement functions often need to access
     unexported symbols (e.g. static functions), which "normal"
     relocations don't allow.

  2) Late module patching: this is the ability for a KLP module to
     bypass normal module dependencies, such that the KLP module can be
     loaded *before* a to-be-patched module.  This means that
     relocations which need to access symbols in the to-be-patched
     module might need to be applied to the KLP module well after it has
     been loaded.

Non-late-patched KLP relocations are applied from the KLP module's init
function.  That usually works fine, unless the patched code wants to use
alternatives, paravirt patching, jump tables, or some other special
section which needs relocations.  Then we run into ordering issues and
crashes.

In order for those special sections to work properly, the KLP
relocations should be applied *before* the special section init code
runs, such as apply_paravirt(), apply_alternatives(), or
jump_label_apply_nops().

You might think the obvious solution would be to move the KLP relocation
initialization earlier, but it's not necessarily that simple.  The
problem is the above-mentioned late module patching, for which KLP
relocations can get applied well after the KLP module is loaded.

To "fix" this issue in the past, we created .klp.arch sections:

  .klp.arch.{module}..altinstructions
  .klp.arch.{module}..parainstructions

Those sections allow KLP late module patching code to call
apply_paravirt() and apply_alternatives() after the module-specific KLP
relocations (.klp.rela.{module}.{section}) have been applied.

But that has a lot of drawbacks, including code complexity, the need for
arch-specific code, and the (per-arch) danger that we missed some
special section -- for example the __jump_table section which is used
for jump labels.

It turns out there's a simpler and more functional approach.  There are
two kinds of KLP relocation sections:

  1) vmlinux-specific KLP relocation sections

     .klp.rela.vmlinux.{sec}

     These are relocations (applied to the KLP module) which reference
     unexported vmlinux symbols.

  2) module-specific KLP relocation sections

     .klp.rela.{module}.{sec}:

     These are relocations (applied to the KLP module) which reference
     unexported or exported module symbols.

Up until now, these have been treated the same.  However, they're
inherently different.

Because of late module patching, module-specific KLP relocations can be
applied very late, thus they can create the ordering headaches described
above.

But vmlinux-specific KLP relocations don't have that problem.  There's
nothing to prevent them from being applied earlier.  So apply them at
the same time as normal relocations, when the KLP module is being
loaded.

This means that for vmlinux-specific KLP relocations, we no longer have
any ordering issues.  vmlinux-referencing jump labels, alternatives, and
paravirt patching will work automatically, without the need for the
.klp.arch hacks.

All that said, for module-specific KLP relocations, the ordering
problems still exist and we *do* still need .klp.arch.  Or do we?  Stay
tuned.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:42 +02:00
Josh Poimboeuf
dcf550e52f livepatch: Disallow vmlinux.ko
This is purely a theoretical issue, but if there were a module named
vmlinux.ko, the livepatch relocation code wouldn't be able to
distinguish between vmlinux-specific and vmlinux.o-specific KLP
relocations.

If CONFIG_LIVEPATCH is enabled, don't allow a module named vmlinux.ko.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2020-05-08 00:12:42 +02:00
Eric W. Biederman
96ecee29b0 exec: Merge install_exec_creds into setup_new_exec
The two functions are now always called one right after the
other so merge them together to make future maintenance easier.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-05-07 16:55:47 -05:00
Zou Wei
192b7993b3 tracing: Make tracing_snapshot_instance_cond() static
Fix the following sparse warning:

kernel/trace/trace.c:950:6: warning: symbol 'tracing_snapshot_instance_cond'
was not declared. Should it be static?

Link: http://lkml.kernel.org/r/1587614905-48692-1-git-send-email-zou_wei@huawei.com

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-07 13:32:58 -04:00
Steven Rostedt (VMware)
11f5efc3ab tracing: Add a vmalloc_sync_mappings() for safe measure
x86_64 lazily maps in the vmalloc pages, and the way this works with per_cpu
areas can be complex, to say the least. Mappings may happen at boot up, and
if nothing synchronizes the page tables, those page mappings may not be
synced till they are used. This causes issues for anything that might touch
one of those mappings in the path of the page fault handler. When one of
those unmapped mappings is touched in the page fault handler, it will cause
another page fault, which in turn will cause a page fault, and leave us in
a loop of page faults.

Commit 763802b53a ("x86/mm: split vmalloc_sync_all()") split
vmalloc_sync_all() into vmalloc_sync_unmappings() and
vmalloc_sync_mappings(), as on system exit, it did not need to do a full
sync on x86_64 (although it still needed to be done on x86_32). By chance,
the vmalloc_sync_all() would synchronize the page mappings done at boot up
and prevent the per cpu area from being a problem for tracing in the page
fault handler. But when that synchronization in the exit of a task became a
nop, it caused the problem to appear.

Link: https://lore.kernel.org/r/20200429054857.66e8e333@oasis.local.home

Cc: stable@vger.kernel.org
Fixes: 737223fbca ("tracing: Consolidate buffer allocation code")
Reported-by: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Suggested-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-07 13:32:57 -04:00
Steven Rostedt (VMware)
d16a8c3107 tracing: Wait for preempt irq delay thread to finish
Running on a slower machine, it is possible that the preempt delay kernel
thread may still be executing if the module was immediately removed after
added, and this can cause the kernel to crash as the kernel thread might be
executing after its code has been removed.

There's no reason that the caller of the code shouldn't just wait for the
delay thread to finish, as the thread can also be created by a trigger in
the sysfs code, which also has the same issues.

Link: http://lore.kernel.org/r/5EA2B0C8.2080706@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 793937236d ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Reported-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-07 13:32:40 -04:00
Paul E. McKenney
f736e0f1a5 Merge branches 'fixes.2020.04.27a', 'kfree_rcu.2020.04.27a', 'rcu-tasks.2020.04.27a', 'stall.2020.04.27a' and 'torture.2020.05.07a' into HEAD
fixes.2020.04.27a:  Miscellaneous fixes.
kfree_rcu.2020.04.27a:  Changes related to kfree_rcu().
rcu-tasks.2020.04.27a:  Addition of new RCU-tasks flavors.
stall.2020.04.27a:  RCU CPU stall-warning updates.
torture.2020.05.07a:  Torture-test updates.
2020-05-07 10:18:32 -07:00
Paul E. McKenney
3c80b40245 rcutorture: Convert ULONG_CMP_LT() to time_before()
This commit converts three ULONG_CMP_LT() invocations in rcutorture to
time_before() to reflect the fact that they are comparing timestamps to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-07 10:15:29 -07:00
Jason Yan
afbc1574f1 rcutorture: Make rcu_fwds and rcu_fwd_emergency_stop static
This commit fixes the following sparse warning:

kernel/rcu/rcutorture.c:1695:16: warning: symbol 'rcu_fwds' was not declared. Should it be static?
kernel/rcu/rcutorture.c:1696:6: warning: symbol 'rcu_fwd_emergency_stop' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-07 10:15:29 -07:00
Paul E. McKenney
55b2dcf587 rcu: Allow rcutorture to starve grace-period kthread
This commit provides an rcutorture.stall_gp_kthread module parameter
to allow rcutorture to starve the grace-period kthread.  This allows
testing the code that detects such starvation.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-07 10:15:28 -07:00
Paul E. McKenney
19a8ff956c rcutorture: Add flag to produce non-busy-wait task stalls
This commit aids testing of RCU task stall warning messages by adding
an rcutorture.stall_cpu_block module parameter that results in the
induced stall sleeping within the RCU read-side critical section.
Spinning with interrupts disabled is still available via the
rcutorture.stall_cpu_irqsoff module parameter, and specifying neither
of these two module parameters will spin with preemption disabled.

Note that sleeping (as opposed to preemption) results in additional
complaints from RCU at context-switch time, so yet more testing.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-07 10:15:28 -07:00
Andy Shevchenko
a135020736 kgdb: Drop malformed kernel doc comment
Kernel doc does not understand POD variables to be referred to.

.../debug_core.c:73: warning: cannot understand function prototype:
'int                             kgdb_connected; '

Convert kernel doc to pure comment.

Fixes: dc7d552705 ("kgdb: core")
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-07 15:16:19 +01:00
Qais Yousef
fb7fb84a0c cpu/hotplug: Remove __freeze_secondary_cpus()
The refactored function is no longer required as the codepaths that call
freeze_secondary_cpus() are all suspend/resume related now.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: https://lkml.kernel.org/r/20200430114004.17477-2-qais.yousef@arm.com
2020-05-07 15:18:41 +02:00
Qais Yousef
5655585589 cpu/hotplug: Remove disable_nonboot_cpus()
The single user could have called freeze_secondary_cpus() directly.

Since this function was a source of confusion, remove it as it's
just a pointless wrapper.

While at it, rename enable_nonboot_cpus() to thaw_secondary_cpus() to
preserve the naming symmetry.

Done automatically via:

	git grep -l enable_nonboot_cpus | xargs sed -i 's/enable_nonboot_cpus/thaw_secondary_cpus/g'

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: https://lkml.kernel.org/r/20200430114004.17477-1-qais.yousef@arm.com
2020-05-07 15:18:40 +02:00
David S. Miller
3793faad7b Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Conflicts were all overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-06 22:10:13 -07:00
Marco Elver
19acd03d95 kcsan: Add __kcsan_{enable,disable}_current() variants
The __kcsan_{enable,disable}_current() variants only call into KCSAN if
KCSAN is enabled for the current compilation unit. Note: This is
typically not what we want, as we usually want to ensure that even calls
into other functions still have KCSAN disabled.

These variants may safely be used in header files that are shared
between regular kernel code and code that does not link the KCSAN
runtime.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-06 10:58:46 -07:00
Masami Hiramatsu
5b4dcd2d20 tracing/kprobes: Reject new event if loc is NULL
Reject the new event which has NULL location for kprobes.
For kprobes, user must specify at least the location.

Link: http://lkml.kernel.org/r/158779376597.6082.1411212055469099461.stgit@devnote2

Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 2a588dd1d5 ("tracing: Add kprobe event command generation functions")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-06 09:04:11 -04:00
Masami Hiramatsu
da0f1f4167 tracing/boottime: Fix kprobe event API usage
Fix boottime kprobe events to use API correctly for
multiple events.

For example, when we set a multiprobe kprobe events in
bootconfig like below,

  ftrace.event.kprobes.myevent {
  	probes = "vfs_read $arg1 $arg2", "vfs_write $arg1 $arg2"
  }

This cause an error;

  trace_boot: Failed to add probe: p:kprobes/myevent (null)  vfs_read $arg1 $arg2  vfs_write $arg1 $arg2

This shows the 1st argument becomes NULL and multiprobes
are merged to 1 probe.

Link: http://lkml.kernel.org/r/158779375766.6082.201939936008972838.stgit@devnote2

Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 29a1548105 ("tracing: Change trace_boot to use kprobe_event interface")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-06 09:04:11 -04:00
Masami Hiramatsu
dcbd21c9fc tracing/kprobes: Fix a double initialization typo
Fix a typo that resulted in an unnecessary double
initialization to addr.

Link: http://lkml.kernel.org/r/158779374968.6082.2337484008464939919.stgit@devnote2

Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Fixes: c7411a1a12 ("tracing/kprobe: Check whether the non-suffixed symbol is notrace")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-05-06 09:04:11 -04:00
Christoph Hellwig
c3b3f52476 signal: refactor copy_siginfo_to_user32
Factor out a copy_siginfo_to_external32 helper from
copy_siginfo_to_user32 that fills out the compat_siginfo, but does so
on a kernel space data structure.  With that we can let architectures
override copy_siginfo_to_user32 with their own implementations using
copy_siginfo_to_external32.  That allows moving the x32 SIGCHLD purely
to x86 architecture code.

As a nice side effect copy_siginfo_to_external32 also comes in handy
for avoiding a set_fs() call in the coredump code later on.

Contains improvements from Eric W. Biederman <ebiederm@xmission.com>
and Arnd Bergmann <arnd@arndb.de>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-05 16:46:09 -04:00
Arnd Bergmann
5447e8e01e sysctl: Fix unused function warning
The newly added bpf_stats_handler function has the wrong #ifdef
check around it, leading to an unused-function warning when
CONFIG_SYSCTL is disabled:

kernel/sysctl.c:205:12: error: unused function 'bpf_stats_handler' [-Werror,-Wunused-function]
static int bpf_stats_handler(struct ctl_table *table, int write,

Fix the check to match the reference.

Fixes: d46edd671a ("bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200505140734.503701-1-arnd@arndb.de
2020-05-05 11:59:32 -07:00
Sean Fu
f187b6974f workqueue: Use IS_ERR and PTR_ERR instead of PTR_ERR_OR_ZERO.
Replace inline function PTR_ERR_OR_ZERO with IS_ERR and PTR_ERR to
remove redundant parameter definitions and checks.
Reduce code size.
Before:
   text	   data	    bss	    dec	    hex	filename
  47510	   5979	    840	  54329	   d439	kernel/workqueue.o
After:
   text	   data	    bss	    dec	    hex	filename
  47474	   5979	    840	  54293	   d415	kernel/workqueue.o

Signed-off-by: Sean Fu <fxinrong@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2020-05-05 11:56:07 -04:00
Andrii Nakryiko
138c67677f bpf: Fix use-after-free of bpf_link when priming half-fails
If bpf_link_prime() succeeds to allocate new anon file, but then fails to
allocate ID for it, link priming is considered to be failed and user is
supposed ot be able to directly kfree() bpf_link, because it was never exposed
to user-space.

But at that point file already keeps a pointer to bpf_link and will eventually
call bpf_link_release(), so if bpf_link was kfree()'d by caller, that would
lead to use-after-free.

Fix this by first allocating ID and only then allocating file. Adding ID to
link_idr is ok, because link at that point still doesn't have its ID set, so
no user-space process can create a new FD for it.

Fixes: a3b80e1078 ("bpf: Allocate ID for bpf_link")
Reported-by: syzbot+39b64425f91b5aab714d@syzkaller.appspotmail.com
Suggested-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200501185622.3088964-1-andriin@fb.com
2020-05-01 15:13:05 -07:00
Song Liu
d46edd671a bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS
Currently, sysctl kernel.bpf_stats_enabled controls BPF runtime stats.
Typical userspace tools use kernel.bpf_stats_enabled as follows:

  1. Enable kernel.bpf_stats_enabled;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Disable kernel.bpf_stats_enabled.

The problem with this approach is that only one userspace tool can toggle
this sysctl. If multiple tools toggle the sysctl at the same time, the
measurement may be inaccurate.

To fix this problem while keep backward compatibility, introduce a new
bpf command BPF_ENABLE_STATS. On success, this command enables stats and
returns a valid fd. BPF_ENABLE_STATS takes argument "type". Currently,
only one type, BPF_STATS_RUN_TIME, is supported. We can extend the
command to support other types of stats in the future.

With BPF_ENABLE_STATS, user space tool would have the following flow:

  1. Get a fd with BPF_ENABLE_STATS, and make sure it is valid;
  2. Check program run_time_ns;
  3. Sleep for the monitoring period;
  4. Check program run_time_ns again, calculate the difference;
  5. Close the fd.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200430071506.1408910-2-songliubraving@fb.com
2020-05-01 10:36:32 -07:00
Zheng Bin
db9ff6ecf6 audit: make symbol 'audit_nfcfgs' static
Fix sparse warnings:

kernel/auditsc.c:138:32: warning: symbol 'audit_nfcfgs' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-01 12:24:07 -04:00
Christophe Leroy
41cd780524 uaccess: Selectively open read or write user access
When opening user access to only perform reads, only open read access.
When opening user access to only perform writes, only open write
access.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2e73bc57125c2c6ab12a587586a4eed3a47105fc.1585898438.git.christophe.leroy@c-s.fr
2020-05-01 12:35:21 +10:00
Wei Yang
b1d1779e5e sched/core: Simplify sched_init()
Currently root_task_group.shares and cfs_bandwidth are initialized for
each online cpu, which not necessary.

Let's take it out to do it only once.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200423214443.29994-1-richard.weiyang@gmail.com
2020-04-30 20:14:42 +02:00
Muchun Song
17c891ab34 sched/fair: Use __this_cpu_read() in wake_wide()
The code is executed with preemption(and interrupts) disabled,
so it's safe to use __this_cpu_write().

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200421144123.33580-1-songmuchun@bytedance.com
2020-04-30 20:14:41 +02:00
Peter Zijlstra
bf2c59fce4 sched/core: Fix illegal RCU from offline CPUs
In the CPU-offline process, it calls mmdrop() after idle entry and the
subsequent call to cpuhp_report_idle_dead(). Once execution passes the
call to rcu_report_dead(), RCU is ignoring the CPU, which results in
lockdep complaining when mmdrop() uses RCU from either memcg or
debugobjects below.

Fix it by cleaning up the active_mm state from BP instead. Every arch
which has CONFIG_HOTPLUG_CPU should have already called idle_task_exit()
from AP. The only exception is parisc because it switches them to
&init_mm unconditionally (see smp_boot_one_cpu() and smp_cpu_init()),
but the patch will still work there because it calls mmgrab(&init_mm) in
smp_cpu_init() and then should call mmdrop(&init_mm) in finish_cpu().

  WARNING: suspicious RCU usage
  -----------------------------
  kernel/workqueue.c:710 RCU or wq_pool_mutex should be held!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  Call Trace:
   dump_stack+0xf4/0x164 (unreliable)
   lockdep_rcu_suspicious+0x140/0x164
   get_work_pool+0x110/0x150
   __queue_work+0x1bc/0xca0
   queue_work_on+0x114/0x120
   css_release+0x9c/0xc0
   percpu_ref_put_many+0x204/0x230
   free_pcp_prepare+0x264/0x570
   free_unref_page+0x38/0xf0
   __mmdrop+0x21c/0x2c0
   idle_task_exit+0x170/0x1b0
   pnv_smp_cpu_kill_self+0x38/0x2e0
   cpu_die+0x48/0x64
   arch_cpu_idle_dead+0x30/0x50
   do_idle+0x2f4/0x470
   cpu_startup_entry+0x38/0x40
   start_secondary+0x7a8/0xa80
   start_secondary_resume+0x10/0x14

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lkml.kernel.org/r/20200401214033.8448-1-cai@lca.pw
2020-04-30 20:14:41 +02:00
Muchun Song
f38f12d1e0 sched/fair: Mark sched_init_granularity __init
Function sched_init_granularity() is only called from __init
functions, so mark it __init as well.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/20200406074750.56533-1-songmuchun@bytedance.com
2020-04-30 20:14:41 +02:00
Huaixin Chang
5a6d6a6ccb sched/fair: Refill bandwidth before scaling
In order to prevent possible hardlockup of sched_cfs_period_timer()
loop, loop count is introduced to denote whether to scale quota and
period or not. However, scale is done between forwarding period timer
and refilling cfs bandwidth runtime, which means that period timer is
forwarded with old "period" while runtime is refilled with scaled
"quota".

Move do_sched_cfs_period_timer() before scaling to solve this.

Fixes: 2e8e192263 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup")
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20200420024421.22442-3-changhuaixin@linux.alibaba.com
2020-04-30 20:14:40 +02:00
Chen Yu
457d1f4657 sched: Extract the task putting code from pick_next_task()
Introduce a new function put_prev_task_balance() to do the balance
when necessary, and then put previous task back to the run queue.
This function is extracted from pick_next_task() to prepare for
future usage by other type of task picking logic.

No functional change.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/5a99860cf66293db58a397d6248bcb2eee326776.1587464698.git.yu.c.chen@intel.com
2020-04-30 20:14:40 +02:00
Chen Yu
d91cecc156 sched: Make newidle_balance() static again
After Commit 6e2df0581f ("sched: Fix pick_next_task() vs 'change'
pattern race"), there is no need to expose newidle_balance() as it
is only used within fair.c file. Change this function back to static again.

No functional change.

Reported-by: kbuild test robot <lkp@intel.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/83cd3030b031ca5d646cd5e225be10e7a0fdd8f5.1587464698.git.yu.c.chen@intel.com
2020-04-30 20:14:40 +02:00
Valentin Schneider
36c5bdc438 sched/topology: Kill SD_LOAD_BALANCE
That flag is set unconditionally in sd_init(), and no one checks for it
anymore. Remove it.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200415210512.805-5-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Valentin Schneider
e669ac8ab9 sched: Remove checks against SD_LOAD_BALANCE
The SD_LOAD_BALANCE flag is set unconditionally for all domains in
sd_init(). By making the sched_domain->flags syctl interface read-only, we
have removed the last piece of code that could clear that flag - as such,
it will now be always present. Rather than to keep carrying it along, we
can work towards getting rid of it entirely.

cpusets don't need it because they can make CPUs be attached to the NULL
domain (e.g. cpuset with sched_load_balance=0), or to a partitioned
root_domain, i.e. a sched_domain hierarchy that doesn't span the entire
system (e.g. root cpuset with sched_load_balance=0 and sibling cpusets with
sched_load_balance=1).

isolcpus apply the same "trick": isolated CPUs are explicitly taken out of
the sched_domain rebuild (using housekeeping_cpumask()), so they get the
NULL domain treatment as well.

Remove the checks against SD_LOAD_BALANCE.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200415210512.805-4-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Valentin Schneider
9818427c62 sched/debug: Make sd->flags sysctl read-only
Writing to the sysctl of a sched_domain->flags directly updates the value of
the field, and goes nowhere near update_top_cache_domain(). This means that
the cached domain pointers can end up containing stale data (e.g. the
domain pointed to doesn't have the relevant flag set anymore).

Explicit domain walks that check for flags will be affected by
the write, but this won't be in sync with the cached pointers which will
still point to the domains that were cached at the last sched_domain
build.

In other words, writing to this interface is playing a dangerous game. It
could be made to trigger an update of the cached sched_domain pointers when
written to, but this does not seem to be worth the trouble. Make it
read-only.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200415210512.805-3-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Valentin Schneider
45da27732b sched/fair: find_idlest_group(): Remove unused sd_flag parameter
The last use of that parameter was removed by commit

  57abff067a ("sched/fair: Rework find_idlest_group()")

Get rid of the parameter.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200415210512.805-2-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Jann Horn
586b58cac8 exit: Move preemption fixup up, move blocking operations down
With CONFIG_DEBUG_ATOMIC_SLEEP=y and CONFIG_CGROUPS=y, kernel oopses in
non-preemptible context look untidy; after the main oops, the kernel prints
a "sleeping function called from invalid context" report because
exit_signals() -> cgroup_threadgroup_change_begin() -> percpu_down_read()
can sleep, and that happens before the preempt_count_set(PREEMPT_ENABLED)
fixup.

It looks like the same thing applies to profile_task_exit() and
kcov_task_exit().

Fix it by moving the preemption fixup up and the calls to
profile_task_exit() and kcov_task_exit() down.

Fixes: 1dc0fffc48 ("sched/core: Robustify preemption leak checks")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200305220657.46800-1-jannh@google.com
2020-04-30 20:14:38 +02:00
Peng Wang
64297f2b03 sched/fair: Simplify the code of should_we_balance()
We only consider group_balance_cpu() after there is no idle
cpu. So, just do comparison before return at these two cases.

Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/245c792f0e580b3ca342ad61257f4c066ee0f84f.1586594833.git.rocking@linux.alibaba.com
2020-04-30 20:14:38 +02:00
Josh Don
ab93a4bc95 sched/fair: Remove distribute_running from CFS bandwidth
This is mostly a revert of commit:

  baa9be4ffb ("sched/fair: Fix throttle_list starvation with low CFS quota")

The primary use of distribute_running was to determine whether to add
throttled entities to the head or the tail of the throttled list. Now
that we always add to the tail, we can remove this field.

The other use of distribute_running is in the slack_timer, so that we
don't start a distribution while one is already running. However, even
in the event that this race occurs, it is fine to have two distributions
running (especially now that distribute grabs the cfs_b->lock to
determine remaining quota before assigning).

Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Tested-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20200410225208.109717-3-joshdon@google.com
2020-04-30 20:14:38 +02:00
Paul Turner
e98fa02c4f sched/fair: Eliminate bandwidth race between throttling and distribution
There is a race window in which an entity begins throttling before quota
is added to the pool, but does not finish throttling until after we have
finished with distribute_cfs_runtime(). This entity is not observed by
distribute_cfs_runtime() because it was not on the throttled list at the
time that distribution was running. This race manifests as rare
period-length statlls for such entities.

Rather than heavy-weight the synchronization with the progress of
distribution, we can fix this by aborting throttling if bandwidth has
become available. Otherwise, we immediately add the entity to the
throttled list so that it can be observed by a subsequent distribution.

Additionally, we can remove the case of adding the throttled entity to
the head of the throttled list, and simply always add to the tail.
Thanks to 26a8b12747, distribute_cfs_runtime() no longer holds onto
its own pool of runtime. This means that if we do hit the !assign and
distribute_running case, we know that distribution is about to end.

Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Ben Segall <bsegall@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20200410225208.109717-2-joshdon@google.com
2020-04-30 20:14:38 +02:00
Xie XiuQi
f080d93e1d sched/debug: Fix trival print_task() format
Ensure leave one space between state and task name.

w/o patch:
runnable tasks:
 S           task   PID         tree-key  switches  prio     wait
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200414125721.195801-1-xiexiuqi@huawei.com
2020-04-30 20:14:37 +02:00
Barret Rhoden
2ed6edd33a perf: Add cond_resched() to task_function_call()
Under rare circumstances, task_function_call() can repeatedly fail and
cause a soft lockup.

There is a slight race where the process is no longer running on the cpu
we targeted by the time remote_function() runs.  The code will simply
try again.  If we are very unlucky, this will continue to fail, until a
watchdog fires.  This can happen in a heavily loaded, multi-core virtual
machine.

Reported-by: syzbot+bb4935a5c09b5ff79940@syzkaller.appspotmail.com
Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200414222920.121401-1-brho@google.com
2020-04-30 20:14:36 +02:00
Wei Yongjun
7f645462ca bpf: Fix error return code in map_lookup_and_delete_elem()
Fix to return negative error code -EFAULT from the copy_to_user() error
handling case instead of 0, as done elsewhere in this function.

Fixes: bd513cd08f ("bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200430081851.166996-1-weiyongjun1@huawei.com
2020-04-30 16:19:08 +02:00
Eric W. Biederman
2dd8083f6d posix-cpu-timers: Use pids not tasks in lookup
The current posix-cpu-timer code uses pids when holding persistent
references in timers.  However the lookups from clock_id_t still return
tasks that need to be converted into pids for use.

This results in usage being pid->task->pid and that can race with
release_task and de_thread.  This can lead to some not wrong but
surprising results.  Surprising enough that Oleg and I both thought
there were some bugs in the code for a while.

This set of changes modifies the code to just lookup, verify, and return
pids from the clockid_t lookups to remove those potentialy troublesome
races.

Eric W. Biederman (3):
      posix-cpu-timers: Extend rcu_read_lock removing task_struct references
      posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
      posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock

 kernel/time/posix-cpu-timers.c | 102 ++++++++++++++++++-----------------------
 1 file changed, 45 insertions(+), 57 deletions(-)

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-30 06:43:44 -05:00
Oleg Nesterov
1dd694a1b7 remove the no longer needed pid_alive() check in __task_pid_nr_ns()
Starting from 2c4704756c ("pids: Move the pgrp and session pid pointers
from task_struct to signal_struct") __task_pid_nr_ns() doesn't dereference
task->group_leader, we can remove the pid_alive() check.

pid_nr_ns() has to check pid != NULL anyway, pid_alive() just adds the
unnecessary confusion.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-04-30 06:40:14 -05:00
Daniel Jordan
3c2214b602 padata: add separate cpuhp node for CPUHP_PADATA_DEAD
Removing the pcrypt module triggers this:

  general protection fault, probably for non-canonical
    address 0xdead000000000122
  CPU: 5 PID: 264 Comm: modprobe Not tainted 5.6.0+ #2
  Hardware name: QEMU Standard PC
  RIP: 0010:__cpuhp_state_remove_instance+0xcc/0x120
  Call Trace:
   padata_sysfs_release+0x74/0xce
   kobject_put+0x81/0xd0
   padata_free+0x12/0x20
   pcrypt_exit+0x43/0x8ee [pcrypt]

padata instances wrongly use the same hlist node for the online and dead
states, so __padata_free()'s second cpuhp remove call chokes on the node
that the first poisoned.

cpuhp multi-instance callbacks only walk forward in cpuhp_step->list and
the same node is linked in both the online and dead lists, so the list
corruption that results from padata_alloc() adding the node to a second
list without removing it from the first doesn't cause problems as long
as no instances are freed.

Avoid the issue by giving each state its own node.

Fixes: 894c9ef978 ("padata: validate cpumask without removed CPU during offline")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-04-30 15:19:33 +10:00
Arnd Bergmann
449e14bfdb bpf: Fix unused variable warning
Hiding the only using of bpf_link_type_strs[] in an #ifdef causes
an unused-variable warning:

kernel/bpf/syscall.c:2280:20: error: 'bpf_link_type_strs' defined but not used [-Werror=unused-variable]
 2280 | static const char *bpf_link_type_strs[] = {

Move the definition into the same #ifdef.

Fixes: f2e10bff16 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200429132217.1294289-1-arnd@arndb.de
2020-04-30 00:21:22 +02:00
Jakub Sitnicki
64d85290d7 bpf: Allow bpf_map_lookup_elem for SOCKMAP and SOCKHASH
White-list map lookup for SOCKMAP/SOCKHASH from BPF. Lookup returns a
pointer to a full socket and acquires a reference if necessary.

To support it we need to extend the verifier to know that:

 (1) register storing the lookup result holds a pointer to socket, if
     lookup was done on SOCKMAP/SOCKHASH, and that

 (2) map lookup on SOCKMAP/SOCKHASH is a reference acquiring operation,
     which needs a corresponding reference release with bpf_sk_release.

On sock_map side, lookup handlers exposed via bpf_map_ops now bump
sk_refcnt if socket is reference counted. In turn, bpf_sk_select_reuseport,
the only in-kernel user of SOCKMAP/SOCKHASH ops->map_lookup_elem, was
updated to release the reference.

Sockets fetched from a map can be used in the same way as ones returned by
BPF socket lookup helpers, such as bpf_sk_lookup_tcp. In particular, they
can be used with bpf_sk_assign to direct packets toward a socket on TC
ingress path.

Suggested-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200429181154.479310-2-jakub@cloudflare.com
2020-04-29 23:30:59 +02:00
Eric W. Biederman
964987738b posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
Now that the codes store references to pids instead of referendes to
tasks.  Looking up a task for a clock instead of looking up a struct
pid makes the code more difficult to verify it is correct than
necessary.

In posix_cpu_timers_create get_task_pid can race with release_task for
threads and return a NULL pid.  As put_pid and cpu_timer_task_rcu
handle NULL pids just fine the code works without problems but it is
an extra case to consider and keep in mind while verifying and
modifying the code.

There are races with de_thread to consider that only don't apply
because thread clocks are only allowed for threads in the same
thread_group.

So instead of leaving a burden for people making modification to the
code in the future return a rcu protected struct pid for the clock
instead.

The logic for __get_task_for_pid and lookup_task has been folded into
the new function pid_for_clock with the only change being the logic
has been modified from working on a task to working on a pid that
will be returned.

In posix_cpu_clock_get instead of calling pid_for_clock checking the
result and then calling pid_task to get the task.  The result of
pid_for_clock is fed directly into pid_task.  This is safe because
pid_task handles NULL pids.  As such an extra error check was
unnecessary.

Instead of hiding the flag that enables the special clock_gettime
handling, I have made the 3 callers just pass the flag in themselves.
That is less code and seems just as simple to work with as the
wrapper functions.

Historically the clock_gettime special case of allowing a process
clock to be found by the thread id did not even exist [33ab0fec33]
but Thomas Gleixner reports that he has found code that uses that
functionality [55e8c8eb2c].

Link: https://lkml.kernel.org/r/87zhaxqkwa.fsf@nanos.tec.linutronix.de/
Ref: 33ab0fec33 ("posix-timers: Consolidate posix_cpu_clock_get()")
Ref: 55e8c8eb2c ("posix-cpu-timers: Store a reference to a pid not a task")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29 08:14:41 -05:00
Eric W. Biederman
fece98260f posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
Taking a clock and returning a pid_type is a more general and
a superset of taking a timer and returning a pid_type.

Perform this generalization so that future changes may use
this code on clocks as well as timers.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29 07:14:51 -05:00
Eric W. Biederman
9bf7c32409 posix-cpu-timers: Extend rcu_read_lock removing task_struct references
Now that the code stores of pid references it is no longer necessary
or desirable to take a reference on task_struct in __get_task_for_clock.

Instead extend the scope of rcu_read_lock and remove the reference
counting on struct task_struct entirely.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-29 07:14:12 -05:00
Andrii Nakryiko
f2e10bff16 bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link
Add ability to fetch bpf_link details through BPF_OBJ_GET_INFO_BY_FD command.
Also enhance show_fdinfo to potentially include bpf_link type-specific
information (similarly to obj_info).

Also introduce enum bpf_link_type stored in bpf_link itself and expose it in
UAPI. bpf_link_tracing also now will store and return bpf_attach_type.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-5-andriin@fb.com
2020-04-28 17:27:08 -07:00
Andrii Nakryiko
2d602c8cf4 bpf: Support GET_FD_BY_ID and GET_NEXT_ID for bpf_link
Add support to look up bpf_link by ID and iterate over all existing bpf_links
in the system. GET_FD_BY_ID code handles not-yet-ready bpf_link by checking
that its ID hasn't been set to non-zero value yet. Setting bpf_link's ID is
done as the very last step in finalizing bpf_link, together with installing
FD. This approach allows users of bpf_link in kernel code to not worry about
races between user-space and kernel code that hasn't finished attaching and
initializing bpf_link.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-4-andriin@fb.com
2020-04-28 17:27:08 -07:00
Andrii Nakryiko
a3b80e1078 bpf: Allocate ID for bpf_link
Generate ID for each bpf_link using IDR, similarly to bpf_map and bpf_prog.
bpf_link creation, initialization, attachment, and exposing to user-space
through FD and ID is a complicated multi-step process, abstract it away
through bpf_link_primer and bpf_link_prime(), bpf_link_settle(), and
bpf_link_cleanup() internal API. They guarantee that until bpf_link is
properly attached, user-space won't be able to access partially-initialized
bpf_link either from FD or ID. All this allows to simplify bpf_link attachment
and error handling code.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-3-andriin@fb.com
2020-04-28 17:27:08 -07:00
Andrii Nakryiko
f9d041271c bpf: Refactor bpf_link update handling
Make bpf_link update support more generic by making it into another
bpf_link_ops methods. This allows generic syscall handling code to be agnostic
to various conditionally compiled features (e.g., the case of
CONFIG_CGROUP_BPF). This also allows to keep link type-specific code to remain
static within respective code base. Refactor existing bpf_cgroup_link code and
take advantage of this.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200429001614.1544-2-andriin@fb.com
2020-04-28 17:27:07 -07:00
Richard Guy Briggs
a45d88530b netfilter: add audit table unregister actions
Audit the action of unregistering ebtables and x_tables.

See: https://github.com/linux-audit/audit-kernel/issues/44

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-28 18:11:36 -04:00
Richard Guy Briggs
c4dad0aab3 audit: tidy and extend netfilter_cfg x_tables
NETFILTER_CFG record generation was inconsistent for x_tables and
ebtables configuration changes.  The call was needlessly messy and there
were supporting records missing at times while they were produced when
not requested.  Simplify the logging call into a new audit_log_nfcfg
call.  Honour the audit_enabled setting while more consistently
recording information including supporting records by tidying up dummy
checks.

Add an op= field that indicates the operation being performed (register
or replace).

Here is the enhanced sample record:
  type=NETFILTER_CFG msg=audit(1580905834.919:82970): table=filter family=2 entries=83 op=replace

Generate audit NETFILTER_CFG records on ebtables table registration.
Previously this was being done for x_tables registration and replacement
operations and ebtables table replacement only.

See: https://github.com/linux-audit/audit-kernel/issues/25
See: https://github.com/linux-audit/audit-kernel/issues/35
See: https://github.com/linux-audit/audit-kernel/issues/43

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-28 17:52:42 -04:00
Eric W. Biederman
c7f5194054 posix-cpu-timer: Unify the now redundant code in lookup_task
Now that both !thread paths through lookup_task call
thread_group_leader, unify them into the single test at the end of
lookup_task.

This unification just makes it clear what is happening in the gettime
special case of lookup_task.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-28 16:46:04 -05:00
Eric W. Biederman
8feebc6713 posix-cpu-timer: Tidy up group_leader logic in lookup_task
Replace has_group_leader_pid with thread_group_leader.  Years ago Oleg
suggested changing thread_group_leader to has_group_leader_pid to handle
races.  Looking at the code then and now I don't see how it ever helped.
Especially as then the code really did need to be the
thread_group_leader.

Today it doesn't make a difference if thread_group_leader races with
de_thread as the task returned from lookup_task in the non-thread case is
just used to find values in task->signal.

Since the races with de_thread have never been handled revert
has_group_header_pid to thread_group_leader for clarity.

Update the comment in lookup_task to remove implementation details that
are no longer true and to mention task->signal instead of task->sighand,
as the relevant cpu timer details are all in task->signal.

Ref: 55e8c8eb2c ("posix-cpu-timers: Store a reference to a pid not a task")
Ref: c0deae8c95 ("posix-cpu-timers: Rcu_read_lock/unlock protect find_task_by_vpid call")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-04-28 16:42:03 -05:00
Eric W. Biederman
6b03d1304a proc: Ensure we see the exit of each process tid exactly once
When the thread group leader changes during exec and the old leaders
thread is reaped proc_flush_pid will flush the dentries for the entire
process because the leader still has it's original pid.

Fix this by exchanging the pids in an rcu safe manner,
and wrapping the code to do that up in a helper exchange_tids.

When I removed switch_exec_pids and introduced this behavior
in d73d65293e ("[PATCH] pidhash: kill switch_exec_pids") there
really was nothing that cared as flushing happened with
the cached dentry and de_thread flushed both of them on exec.

This lack of fully exchanging pids became a problem a few months later
when I introduced 48e6484d49 ("[PATCH] proc: Rewrite the proc dentry
flush on exit optimization").  Which overlooked the de_thread case
was no longer swapping pids, and I was looking up proc dentries
by task->pid.

The current behavior isn't properly a bug as everything in proc will
continue to work correctly just a little bit less efficiently.  Fix
this just so there are no little surprise corner cases waiting to bite
people.

-- Oleg points out this could be an issue in next_tgid in proc where
   has_group_leader_pid is called, and reording some of the assignments
   should fix that.

-- Oleg points out this will break the 10 year old hack in __exit_signal.c
>	/*
>	 * This can only happen if the caller is de_thread().
>	 * FIXME: this is the temporary hack, we should teach
>	 * posix-cpu-timers to handle this case correctly.
>	 */
>	if (unlikely(has_group_leader_pid(tsk)))
>		posix_cpu_timers_exit_group(tsk);

The code in next_tgid has been changed to use PIDTYPE_TGID,
and the posix cpu timers code has been fixed so it does not
need the 10 year old hack, so this should be safe to merge
now.

Link: https://lore.kernel.org/lkml/87h7x3ajll.fsf_-_@x220.int.ebiederm.org/
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 48e6484d49 ("[PATCH] proc: Rewrite the proc dentry flush on exit optimization").
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-04-28 16:13:58 -05:00
Daniel Borkmann
0b54142e4b Merge branch 'work.sysctl' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull in Christoph Hellwig's series that changes the sysctl's ->proc_handler
methods to take kernel pointers instead. It gets rid of the set_fs address
space overrides used by BPF. As per discussion, pull in the feature branch
into bpf-next as it relates to BPF sysctl progs.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200427071508.GV23230@ZenIV.linux.org.uk/T/
2020-04-28 21:23:38 +02:00
Luis Chamberlain
3740d93e37 coredump: fix crash when umh is disabled
Commit 64e90a8acb ("Introduce STATIC_USERMODEHELPER to mediate
call_usermodehelper()") added the optiont to disable all
call_usermodehelper() calls by setting STATIC_USERMODEHELPER_PATH to
an empty string. When this is done, and crashdump is triggered, it
will crash on null pointer dereference, since we make assumptions
over what call_usermodehelper_exec() did.

This has been reported by Sergey when one triggers a a coredump
with the following configuration:

```
CONFIG_STATIC_USERMODEHELPER=y
CONFIG_STATIC_USERMODEHELPER_PATH=""
kernel.core_pattern = |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %e
```

The way disabling the umh was designed was that call_usermodehelper_exec()
would just return early, without an error. But coredump assumes
certain variables are set up for us when this happens, and calls
ile_start_write(cprm.file) with a NULL file.

[    2.819676] BUG: kernel NULL pointer dereference, address: 0000000000000020
[    2.819859] #PF: supervisor read access in kernel mode
[    2.820035] #PF: error_code(0x0000) - not-present page
[    2.820188] PGD 0 P4D 0
[    2.820305] Oops: 0000 [#1] SMP PTI
[    2.820436] CPU: 2 PID: 89 Comm: a Not tainted 5.7.0-rc1+ #7
[    2.820680] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190711_202441-buildvm-armv7-10.arm.fedoraproject.org-2.fc31 04/01/2014
[    2.821150] RIP: 0010:do_coredump+0xd80/0x1060
[    2.821385] Code: e8 95 11 ed ff 48 c7 c6 cc a7 b4 81 48 8d bd 28 ff
ff ff 89 c2 e8 70 f1 ff ff 41 89 c2 85 c0 0f 84 72 f7 ff ff e9 b4 fe ff
ff <48> 8b 57 20 0f b7 02 66 25 00 f0 66 3d 00 8
0 0f 84 9c 01 00 00 44
[    2.822014] RSP: 0000:ffffc9000029bcb8 EFLAGS: 00010246
[    2.822339] RAX: 0000000000000000 RBX: ffff88803f860000 RCX: 000000000000000a
[    2.822746] RDX: 0000000000000009 RSI: 0000000000000282 RDI: 0000000000000000
[    2.823141] RBP: ffffc9000029bde8 R08: 0000000000000000 R09: ffffc9000029bc00
[    2.823508] R10: 0000000000000001 R11: ffff88803dec90be R12: ffffffff81c39da0
[    2.823902] R13: ffff88803de84400 R14: 0000000000000000 R15: 0000000000000000
[    2.824285] FS:  00007fee08183540(0000) GS:ffff88803e480000(0000) knlGS:0000000000000000
[    2.824767] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.825111] CR2: 0000000000000020 CR3: 000000003f856005 CR4: 0000000000060ea0
[    2.825479] Call Trace:
[    2.825790]  get_signal+0x11e/0x720
[    2.826087]  do_signal+0x1d/0x670
[    2.826361]  ? force_sig_info_to_task+0xc1/0xf0
[    2.826691]  ? force_sig_fault+0x3c/0x40
[    2.826996]  ? do_trap+0xc9/0x100
[    2.827179]  exit_to_usermode_loop+0x49/0x90
[    2.827359]  prepare_exit_to_usermode+0x77/0xb0
[    2.827559]  ? invalid_op+0xa/0x30
[    2.827747]  ret_from_intr+0x20/0x20
[    2.827921] RIP: 0033:0x55e2c76d2129
[    2.828107] Code: 2d ff ff ff e8 68 ff ff ff 5d c6 05 18 2f 00 00 01
c3 0f 1f 80 00 00 00 00 c3 0f 1f 80 00 00 00 00 e9 7b ff ff ff 55 48 89
e5 <0f> 0b b8 00 00 00 00 5d c3 66 2e 0f 1f 84 0
0 00 00 00 00 0f 1f 40
[    2.828603] RSP: 002b:00007fffeba5e080 EFLAGS: 00010246
[    2.828801] RAX: 000055e2c76d2125 RBX: 0000000000000000 RCX: 00007fee0817c718
[    2.829034] RDX: 00007fffeba5e188 RSI: 00007fffeba5e178 RDI: 0000000000000001
[    2.829257] RBP: 00007fffeba5e080 R08: 0000000000000000 R09: 00007fee08193c00
[    2.829482] R10: 0000000000000009 R11: 0000000000000000 R12: 000055e2c76d2040
[    2.829727] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[    2.829964] CR2: 0000000000000020
[    2.830149] ---[ end trace ceed83d8c68a1bf1 ]---
```

Cc: <stable@vger.kernel.org> # v4.11+
Fixes: 64e90a8acb ("Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()")
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199795
Reported-by: Tony Vroon <chainsaw@gentoo.org>
Reported-by: Sergey Kvachonok <ravenexp@gmail.com>
Tested-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20200416162859.26518-1-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28 17:54:13 +02:00
Richard Guy Briggs
9d2161bed4 audit: log audit netlink multicast bind and unbind
Log information about programs connecting to and disconnecting from the
audit netlink multicast socket. This is needed so that during
investigations a security officer can tell who or what had access to the
audit trail.  This helps to meet the FAU_SAR.2 requirement for Common
Criteria.

Here is the systemd startup event:
type=PROCTITLE msg=audit(2020-04-22 10:10:21.787:10) : proctitle=/init
type=SYSCALL msg=audit(2020-04-22 10:10:21.787:10) : arch=x86_64 syscall=bind success=yes exit=0 a0=0x19 a1=0x555f4aac7e90 a2=0xc a3=0x7ffcb792ff44 items=0 ppid=0 pid=1 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=systemd exe=/usr/lib/systemd/systemd subj=kernel key=(null)
type=UNKNOWN[1335] msg=audit(2020-04-22 10:10:21.787:10) : pid=1 uid=root auid=unset tty=(none) ses=unset subj=kernel comm=systemd exe=/usr/lib/systemd/systemd nl-mcgrp=1 op=connect res=yes

And events from the test suite that just uses close():
type=PROCTITLE msg=audit(2020-04-22 11:47:08.501:442) : proctitle=/usr/bin/perl -w amcast_joinpart/test
type=SYSCALL msg=audit(2020-04-22 11:47:08.501:442) : arch=x86_64 syscall=bind success=yes exit=0 a0=0x7 a1=0x563004378760 a2=0xc a3=0x0 items=0 ppid=815 pid=818 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1335] msg=audit(2020-04-22 11:47:08.501:442) : pid=818 uid=root auid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=connect res=yes

type=UNKNOWN[1335] msg=audit(2020-04-22 11:47:08.501:443) : pid=818 uid=root auid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=disconnect res=yes

And the events from the test suite using setsockopt with NETLINK_DROP_MEMBERSHIP:
type=PROCTITLE msg=audit(2020-04-22 11:39:53.291:439) : proctitle=/usr/bin/perl -w amcast_joinpart/test
type=SYSCALL msg=audit(2020-04-22 11:39:53.291:439) : arch=x86_64 syscall=bind success=yes exit=0 a0=0x7 a1=0x5560877c2d20 a2=0xc a3=0x0 items=0 ppid=772 pid=775 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1335] msg=audit(2020-04-22 11:39:53.291:439) : pid=775 uid=root auid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=connect res=yes

type=PROCTITLE msg=audit(2020-04-22 11:39:53.292:440) : proctitle=/usr/bin/perl -w amcast_joinpart/test
type=SYSCALL msg=audit(2020-04-22 11:39:53.292:440) : arch=x86_64 syscall=setsockopt success=yes exit=0 a0=0x7 a1=SOL_NETLINK a2=0x2 a3=0x7ffc8366f000 items=0 ppid=772 pid=775 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1335] msg=audit(2020-04-22 11:39:53.292:440) : pid=775 uid=root auid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=disconnect res=yes

Please see the upstream issue tracker at
  https://github.com/linux-audit/audit-kernel/issues/28
With the feature description at
  https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Multicast-Socket-Join-Part
The testsuite support is at
  https://github.com/rgbriggs/audit-testsuite/compare/ghak28-mcast-part-join
  https://github.com/linux-audit/audit-testsuite/pull/93
And the userspace support patch is at
  https://github.com/linux-audit/audit-userspace/pull/114

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-27 18:49:31 -04:00
Ethon Paul
182e073f68 cpu/hotplug: Fix a typo in comment "broadacasted"->"broadcasted"
Signed-off-by: Ethon Paul <ethp@qq.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200417164008.6541-1-ethp@qq.com
2020-04-27 22:42:04 +02:00
Christoph Hellwig
8c1b2bf16d bpf, cgroup: Remove unused exports
Except for a few of the networking hooks called from modular ipv4
or ipv6 code, all of hooks are just called from guaranteed to be
built-in code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20200424064338.538313-2-hch@lst.de
2020-04-27 22:20:22 +02:00
Wei Yongjun
52785b6ae8 kcsan: Use GFP_ATOMIC under spin lock
A spin lock is held in insert_report_filterlist(), so the krealloc()
should use GFP_ATOMIC.  This commit therefore makes this change.

Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:10:10 -07:00
Paul E. McKenney
c9527bebb0 rcutorture: Mark data-race potential for rcu_barrier() test statistics
The n_barrier_successes, n_barrier_attempts, and
n_rcu_torture_barrier_error variables are updated (without access
markings) by the main rcu_barrier() test kthread, and accessed (also
without access markings) by the rcu_torture_stats() kthread.  This of
course can result in KCSAN complaints.

Because the accesses are in diagnostic prints, this commit uses
data_race() to excuse the diagnostic prints from the data race.  If this
were to ever cause bogus statistics prints (for example, due to store
tearing), any misleading information would be disambiguated by the
presence or absence of an rcutorture splat.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely and due to the mild consequences of the
failure, namely a confusing rcutorture console message.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
2020-04-27 11:05:13 -07:00
Paul E. McKenney
3b2a473985 rcutorture: Add KCSAN stubs
This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros to
move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:05:13 -07:00
Paul E. McKenney
33b2b93bd8 rcu: Remove self-stack-trace when all quiescent states seen
When all quiescent states have been seen, it is normally the grace-period
kthread that is in trouble.  Although the existing stack trace from
the current CPU might possibly provide useful information, experience
indicates that there is too much noise for this to be worthwhile.

This commit therefore removes this stack trace from the output.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:04:37 -07:00
Paul E. McKenney
8837582517 rcu: When GP kthread is starved, tag idle threads as false positives
If the grace-period kthread is starved, idle threads' extended quiescent
states are not reported.  These idle threads thus wrongly appear to
be blocking the current grace period.  This commit therefore tags such
idle threads as probable false positives when the grace-period kthread
is being starved.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:04:37 -07:00
Paul E. McKenney
654db05cee rcu: Use data_race() for RCU expedited CPU stall-warning prints
Although the accesses used to determine whether or not an expedited
stall should be printed are an integral part of the concurrency algorithm
governing use of the corresponding variables, the values that are simply
printed are ancillary.  As such, it is best to use data_race() for these
accesses in order to provide the greatest latitude in the use of KCSAN
for the other accesses that are an integral part of the algorithm.  This
commit therefore changes the relevant uses of READ_ONCE() to data_race().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:04:37 -07:00
Paul E. McKenney
e5a971d76d ftrace: Use synchronize_rcu_tasks_rude() instead of ftrace_sync()
This commit replaces the schedule_on_each_cpu(ftrace_sync) instances
with synchronize_rcu_tasks_rude().

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
[ paulmck: Make Kconfig adjustments noted by kbuild test robot. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:53 -07:00
Paul E. McKenney
25246fc831 rcu-tasks: Allow standalone use of TASKS_{TRACE_,}RCU
This commit allows TASKS_TRACE_RCU to be used independently of TASKS_RCU
and vice versa.

[ paulmck: Fix conditional compilation per kbuild test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:53 -07:00
Paul E. McKenney
7e0669c3e9 rcu-tasks: Add IPI failure count to statistics
This commit adds a failure-return count for smp_call_function_single(),
and adds this to the console messages for rcutorture writer stalls and at
the end of rcutorture testing.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:53 -07:00
Paul E. McKenney
edf3775f0a rcu-tasks: Add count for idle tasks on offline CPUs
This commit adds a counter for the number of times the quiescent state
was an idle task associated with an offline CPU, and prints this count
at the end of rcutorture runs and at stall time.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:53 -07:00
Paul E. McKenney
40471509be rcu-tasks: Add rcu_dynticks_zero_in_eqs() effectiveness statistics
This commit adds counts of the number of calls and number of successful
calls to rcu_dynticks_zero_in_eqs(), which are printed at the end
of rcutorture runs and at stall time.  This allows evaluation of the
effectiveness of rcu_dynticks_zero_in_eqs().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
9796e1ae73 rcu-tasks: Make RCU tasks trace also wait for idle tasks
This commit scans the CPUs, adding each CPU's idle task to the list of
tasks that need quiescent states.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
7e3b70e070 rcu-tasks: Handle the running-offline idle-task special case
The idle task corresponding to an offline CPU can appear to be running
while that CPU is offline.  This commit therefore adds checks for this
situation, treating it as a quiescent state.  Because the tasklist scan
and the holdout-list scan now exclude CPU-hotplug operations, readers
on the CPU-hotplug paths are still waited for.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
81b4a7bc3b rcu-tasks: Disable CPU hotplug across RCU tasks trace scans
This commit disables CPU hotplug across RCU tasks trace scans, which
is a first step towards correctly recognizing idle tasks "running" on
offline CPUs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
b38f57c1fe rcu-tasks: Allow rcu_read_unlock_trace() under scheduler locks
The rcu_read_unlock_trace() can invoke rcu_read_unlock_trace_special(),
which in turn can call wake_up().  Therefore, if any scheduler lock is
held across a call to rcu_read_unlock_trace(), self-deadlock can occur.
This commit therefore uses the irq_work facility to defer the wake_up()
to a clean environment where no scheduler locks will be held.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
[ paulmck: Update #includes for m68k per kbuild test robot. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
7d0c9c50c5 rcu-tasks: Avoid IPIing userspace/idle tasks if kernel is so built
Systems running CPU-bound real-time task do not want IPIs sent to CPUs
executing nohz_full userspace tasks.  Battery-powered systems don't
want IPIs sent to idle CPUs in low-power mode.  Unfortunately, RCU tasks
trace can and will send such IPIs in some cases.

Both of these situations occur only when the target CPU is in RCU
dyntick-idle mode, in other words, when RCU is not watching the
target CPU.  This suggests that CPUs in dyntick-idle mode should use
memory barriers in outermost invocations of rcu_read_lock_trace()
and rcu_read_unlock_trace(), which would allow the RCU tasks trace
grace period to directly read out the target CPU's read-side state.
One challenge is that RCU tasks trace is not targeting a specific
CPU, but rather a task.  And that task could switch from one CPU to
another at any time.

This commit therefore uses try_invoke_on_locked_down_task()
and checks for task_curr() in trc_inspect_reader_notrunning().
When this condition holds, the target task is running and cannot move.
If CONFIG_TASKS_TRACE_RCU_READ_MB=y, the new rcu_dynticks_zero_in_eqs()
function can be used to check if the specified integer (in this case,
t->trc_reader_nesting) is zero while the target CPU remains in that same
dyntick-idle sojourn.  If so, the target task is in a quiescent state.
If not, trc_read_check_handler() must indicate failure so that the
grace-period kthread can take appropriate action or retry after an
appropriate delay, as the case may be.

With this change, given CONFIG_TASKS_TRACE_RCU_READ_MB=y, if a given
CPU remains idle or a given task continues executing in nohz_full mode,
the RCU tasks trace grace-period kthread will detect this without the
need to send an IPI.

Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
9ae58d7bd1 rcu-tasks: Add Kconfig option to mediate smp_mb() vs. IPI
This commit provides a new TASKS_TRACE_RCU_READ_MB Kconfig option that
enables use of read-side memory barriers by both rcu_read_lock_trace()
and rcu_read_unlock_trace() when the are executed with the
current->trc_reader_special.b.need_mb flag set.  This flag is currently
never set.  Doing that is the subject of a later commit.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
238dbce39e rcu-tasks: Add grace-period and IPI counts to statistics
This commit adds a grace-period count and a count of IPIs sent since
boot, which is printed in response to rcutorture writer stalls and at
the end of rcutorture testing.  These counts will be used to evaluate
various schemes to reduce the number of IPIs sent.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
276c410448 rcu-tasks: Split ->trc_reader_need_end
This commit splits ->trc_reader_need_end by using the rcu_special union.
This change permits readers to check to see if a memory barrier is
required without any added overhead in the common case where no such
barrier is required.  This commit also adds the read-side checking.
Later commits will add the machinery to properly set the new
->trc_reader_special.b.need_mb field.

This commit also makes rcu_read_unlock_trace_special() tolerate nested
read-side critical sections within interrupt and NMI handlers.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
b0afa0f056 rcu-tasks: Provide boot parameter to delay IPIs until late in grace period
This commit provides a rcupdate.rcu_task_ipi_delay kernel boot parameter
that specifies how old the RCU tasks trace grace period must be before
the grace-period kthread starts sending IPIs.  This delay allows more
tasks to pass through rcu_tasks_qs() quiescent states, thus reducing
(or even eliminating) the number of IPIs that must be sent.

On a short rcutorture test setting this kernel boot parameter to HZ/2
resulted in zero IPIs for all 877 RCU-tasks trace grace periods that
elapsed during that test.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
88092d0c99 rcu-tasks: Add a grace-period start time for throttling and debug
This commit adds a place to record the grace-period start in jiffies.
This will be used by later commits for debugging purposes and to throttle
IPIs early in the grace period.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
43766c3ead rcu-tasks: Make RCU Tasks Trace make use of RCU scheduler hooks
This commit makes the calls to rcu_tasks_qs() detect and report
quiescent states for RCU tasks trace.  If the task is in a quiescent
state and if ->trc_reader_checked is not yet set, the task sets its own
->trc_reader_checked.  This will cause the grace-period kthread to
remove it from the holdout list if it still remains there.

[ paulmck: Fix conditional compilation per kbuild test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
af051ca4e4 rcu-tasks: Make rcutorture writer stall output include GP state
This commit adds grace-period state and time to the rcutorture writer
stall output.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:52 -07:00
Paul E. McKenney
e21408ceec rcu-tasks: Add RCU tasks to rcutorture writer stall output
This commit adds state for each RCU-tasks flavor to the rcutorture
writer stall output.  The initial state is minimal, but you have to
start somewhere.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
[ paulmck: Fixes based on feedback from kbuild test robot. ]
2020-04-27 11:03:51 -07:00
Paul E. McKenney
8fd8ca388c rcu-tasks: Move #ifdef into tasks.h
This commit pushes the #ifdef CONFIG_TASKS_RCU_GENERIC from
kernel/rcu/update.c to kernel/rcu/tasks.h in order to improve
readability as more APIs are added.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
4593e772b5 rcu-tasks: Add stall warnings for RCU Tasks Trace
This commit adds RCU CPU stall warnings for RCU Tasks Trace.  These
dump out any tasks blocking the current grace period, as well as any
CPUs that have not responded to an IPI request.  This happens in two
phases, when initially extracting state from the tasks and later when
waiting for any holdout tasks to check in.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
c1a76c0b6a rcutorture: Add torture tests for RCU Tasks Trace
This commit adds the definitions required to torture the tracing flavor
of RCU tasks.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
d5f177d35c rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks
Because RCU does not watch exception early-entry/late-exit, idle-loop,
or CPU-hotplug execution, protection of tracing and BPF operations is
needlessly complicated.  This commit therefore adds a variant of
Tasks RCU that:

o	Has explicit read-side markers to allow finite grace periods in
	the face of in-kernel loops for PREEMPT=n builds.  These markers
	are rcu_read_lock_trace() and rcu_read_unlock_trace().

o	Protects code in the idle loop, exception entry/exit, and
	CPU-hotplug code paths.  In this respect, RCU-tasks trace is
	similar to SRCU, but with lighter-weight readers.

o	Avoids expensive read-side instruction, having overhead similar
	to that of Preemptible RCU.

There are of course downsides:

o	The grace-period code can send IPIs to CPUs, even when those
	CPUs are in the idle loop or in nohz_full userspace.  This is
	mitigated by later commits.

o	It is necessary to scan the full tasklist, much as for Tasks RCU.

o	There is a single callback queue guarded by a single lock,
	again, much as for Tasks RCU.  However, those early use cases
	that request multiple grace periods in quick succession are
	expected to do so from a single task, which makes the single
	lock almost irrelevant.  If needed, multiple callback queues
	can be provided using any number of schemes.

Perhaps most important, this variant of RCU does not affect the vanilla
flavors, rcu_preempt and rcu_sched.  The fact that RCU Tasks Trace
readers can operate from idle, offline, and exception entry/exit in no
way enables rcu_preempt and rcu_sched readers to do so.

The memory ordering was outlined here:
https://lore.kernel.org/lkml/20200319034030.GX3199@paulmck-ThinkPad-P72/

This effort benefited greatly from off-list discussions of BPF
requirements with Alexei Starovoitov and Andrii Nakryiko.  At least
some of the on-list discussions are captured in the Link: tags below.
In addition, KCSAN was quite helpful in finding some early bugs.

Link: https://lore.kernel.org/lkml/20200219150744.428764577@infradead.org/
Link: https://lore.kernel.org/lkml/87mu8p797b.fsf@nanos.tec.linutronix.de/
Link: https://lore.kernel.org/lkml/20200225221305.605144982@linutronix.de/
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andriin@fb.com>
[ paulmck: Apply feedback from Steve Rostedt and Joel Fernandes. ]
[ paulmck: Decrement trc_n_readers_need_end upon IPI failure. ]
[ paulmck: Fix locking issue reported by rcutorture. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
d01aa2633b rcu-tasks: Code movement to allow more Tasks RCU variants
This commit does nothing but move rcu_tasks_wait_gp() up to a new section
for common code.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
e4fe5dd6f2 rcu-tasks: Further refactor RCU-tasks to allow adding more variants
This commit refactors RCU tasks to allow variants to be added.  These
variants will share the current Tasks-RCU tasklist scan and the holdout
list processing.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
c97d12a63c rcu-tasks: Use unique names for RCU-Tasks kthreads and messages
This commit causes the flavors of RCU Tasks to use different names
for their kthreads and in their console messages.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
3d6e43c75d rcutorture: Add torture tests for RCU Tasks Rude
This commit adds the definitions required to torture the rude flavor of
RCU tasks.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
c84aad7654 rcu-tasks: Add an RCU-tasks rude variant
This commit adds a "rude" variant of RCU-tasks that has as quiescent
states schedule(), cond_resched_tasks_rcu_qs(), userspace execution,
and (in theory, anyway) cond_resched().  In other words, RCU-tasks rude
readers are regions of code with preemption disabled, but excluding code
early in the CPU-online sequence and late in the CPU-offline sequence.
Updates make use of IPIs and force an IPI and a context switch on each
online CPU.  This variant is useful in some situations in tracing.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
[ paulmck: Apply EXPORT_SYMBOL_GPL() feedback from Qiujun Huang. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
[ paulmck: Apply review feedback from Steve Rostedt. ]
2020-04-27 11:03:51 -07:00
Paul E. McKenney
5873b8a94e rcu-tasks: Refactor RCU-tasks to allow variants to be added
This commit splits out generic processing from RCU-tasks-specific
processing in order to allow additional flavors to be added.  It also
adds a def_bool TASKS_RCU_GENERIC to enable the common RCU-tasks
infrastructure code.

This is primarily, but not entirely, a code-movement commit.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
9cf8fc6fab rcutorture: Add a test for synchronize_rcu_mult()
This commit adds a crude test for synchronize_rcu_mult().  This is
currently a smoke test rather than a high-quality stress test.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:51 -07:00
Paul E. McKenney
07e105158d rcu-tasks: Create struct to hold state information
This commit creates an rcu_tasks struct to hold state information for
RCU Tasks.  This is a preparation commit for adding additional flavors
of Tasks RCU, each of which would have its own rcu_tasks struct.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
eacd6f04a1 rcu-tasks: Move Tasks RCU to its own file
This code-movement-only commit is in preparation for adding an additional
flavor of Tasks RCU, which relies on workqueues to detect grace periods.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
5bef8da66a rcu: Add per-task state to RCU CPU stall warnings
Currently, an RCU-preempt CPU stall warning simply lists the PIDs of
those tasks holding up the current grace period.  This can be helpful,
but more can be even more helpful.

To this end, this commit adds the nesting level, whether the task
thinks it was preempted in its current RCU read-side critical section,
whether RCU core has asked this task for a quiescent state, whether the
expedited-grace-period hint is set, and whether the task believes that
it is on the blocked-tasks list (it must be, or it would not be printed,
but if things are broken, best not to take too much for granted).

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
2beaf3280e sched/core: Add function to sample state of locked-down task
A running task's state can be sampled in a consistent manner (for example,
for diagnostic purposes) simply by invoking smp_call_function_single()
on its CPU, which may be obtained using task_cpu(), then having the
IPI handler verify that the desired task is in fact still running.
However, if the task is not running, this sampling can in theory be done
immediately and directly.  In practice, the task might start running at
any time, including during the sampling period.  Gaining a consistent
sample of a not-running task therefore requires that something be done
to lock down the target task's state.

This commit therefore adds a try_invoke_on_locked_down_task() function
that invokes a specified function if the specified task can be locked
down, returning true if successful and if the specified function returns
true.  Otherwise this function simply returns false.  Given that the
function passed to try_invoke_on_nonrunning_task() might be invoked with
a runqueue lock held, that function had better be quite lightweight.

The function is passed the target task's task_struct pointer and the
argument passed to try_invoke_on_locked_down_task(), allowing easy access
to task state and to a location for further variables to be passed in
and out.

Note that the specified function will be called even if the specified
task is currently running.  The function can use ->on_rq and task_curr()
to quickly and easily determine the task's state, and can return false
if this state is not to the function's liking.  The caller of the
try_invoke_on_locked_down_task() would then see the false return value,
and could take appropriate action, for example, trying again later or
sending an IPI if matters are more urgent.

It is expected that use cases such as the RCU CPU stall warning code will
simply return false if the task is currently running.  However, there are
use cases involving nohz_full CPUs where the specified function might
instead fall back to an alternative sampling scheme that relies on heavier
synchronization (such as memory barriers) in the target task.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
[ paulmck: Apply feedback from Peter Zijlstra and Steven Rostedt. ]
[ paulmck: Invoke if running to handle feedback from Mathieu Desnoyers. ]
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
66777e5821 rcu-tasks: Use context-switch hook for PREEMPT=y kernels
Currently, the PREEMPT=y version of rcu_note_context_switch() does not
invoke rcu_tasks_qs(), and we need it to in order to keep RCU Tasks
Trace's IPIs down to a dull roar.  This commit therefore enables this
hook.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
ac3caf8274 rcu: Add comments marking transitions between RCU watching and not
It is not as clear as it might be just where in RCU's idle entry/exit
code RCU stops and starts watching the current CPU.  This commit therefore
adds comments calling out the transitions.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
52b1fc3f79 rcutorture: Add test of holding scheduler locks across rcu_read_unlock()
Now that it should be safe to hold scheduler locks across
rcu_read_unlock(), even in cases where the corresponding RCU read-side
critical section might have been preempted and boosted, the commit adds
a test of this capability to rcutorture.  This has been tested on current
mainline (which can deadlock in this situation), and lockdep duly reported
the expected deadlock.  On -rcu, lockdep is silent, thus far, anyway.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Lai Jiangshan
5f5fa7ea89 rcu: Don't use negative nesting depth in __rcu_read_unlock()
Now that RCU flavors have been consolidated, an RCU-preempt
rcu_read_unlock() in an interrupt or softirq handler cannot possibly
end the RCU read-side critical section.  Consider the old vulnerability
involving rcu_read_unlock() being invoked within such a handler that
interrupted an __rcu_read_unlock_special(), in which a wakeup might be
invoked with a scheduler lock held.  Because rcu_read_unlock_special()
no longer does wakeups in such situations, it is no longer necessary
for __rcu_read_unlock() to set the nesting level negative.

This commit therefore removes this recursion-protection code from
__rcu_read_unlock().

[ paulmck: Let rcu_exp_handler() continue to call rcu_report_exp_rdp(). ]
[ paulmck: Adjust other checks given no more negative nesting. ]
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Lai Jiangshan
f0bdf6d473 rcu: Remove unused ->rcu_read_unlock_special.b.deferred_qs field
The ->rcu_read_unlock_special.b.deferred_qs field is set to true in
rcu_read_unlock_special() but never set to false.  This is not
particularly useful, so this commit removes this field.

The only possible justification for this field is to ease debugging
of RCU deferred quiscent states, but the combination of the other
->rcu_read_unlock_special fields plus ->rcu_blocked_node and of course
->rcu_read_lock_nesting should cover debugging needs.  And if this last
proves incorrect, this patch can always be reverted, along with the
required setting of ->rcu_read_unlock_special.b.deferred_qs to false
in rcu_preempt_deferred_qs_irqrestore().

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Lai Jiangshan
07b4a930fc rcu: Don't set nesting depth negative in rcu_preempt_deferred_qs()
Now that RCU flavors have been consolidated, an RCU-preempt
rcu_read_unlock() in an interrupt or softirq handler cannot possibly
end the RCU read-side critical section.  Consider the old vulnerability
involving rcu_preempt_deferred_qs() being invoked within such a handler
that interrupted an extended RCU read-side critical section, in which
a wakeup might be invoked with a scheduler lock held.  Because
rcu_read_unlock_special() no longer does wakeups in such situations,
it is no longer necessary for rcu_preempt_deferred_qs() to set the
nesting level negative.

This commit therefore removes this recursion-protection code from
rcu_preempt_deferred_qs().

[ paulmck: Fix typo in commit log per Steve Rostedt. ]
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
e4453d8a1c rcu: Make rcu_read_unlock_special() safe for rq/pi locks
The scheduler is currently required to hold rq/pi locks across the entire
RCU read-side critical section or not at all.  This is inconvenient and
leaves traps for the unwary, including the author of this commit.

But now that excessively long grace periods enable scheduling-clock
interrupts for holdout nohz_full CPUs, the nohz_full rescue logic in
rcu_read_unlock_special() can be dispensed with.  In other words, the
rcu_read_unlock_special() function can refrain from doing wakeups unless
such wakeups are guaranteed safe.

This commit therefore avoids unsafe wakeups, freeing the scheduler to
hold rq/pi locks across rcu_read_unlock() even if the corresponding RCU
read-side critical section might have been preempted.  This commit also
updates RCU's requirements documentation.

This commit is inspired by a patch from Lai Jiangshan:
https://lore.kernel.org/lkml/20191102124559.1135-2-laijs@linux.alibaba.com
This commit is further intended to be a step towards his goal of permitting
the inlining of RCU-preempt's rcu_read_lock() and rcu_read_unlock().

Cc: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
c76e7e0bce rcu: Add KCSAN stubs to update.c
This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros
to move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
6be7436d22 rcu: Add rcu_gp_might_be_stalled()
This commit adds rcu_gp_might_be_stalled(), which returns true if there
is some reason to believe that the RCU grace period is stalled.  The use
case is where an RCU free-memory path needs to allocate memory in order
to free it, a situation that should be avoided where possible.

But where it is necessary, there is always the alternative of using
synchronize_rcu() to wait for a grace period in order to avoid the
allocation.  And if the grace period is stalled, allocating memory to
asynchronously wait for it is a bad idea of epic proportions: Far better
to let others use the memory, because these others might actually be
able to free that memory before the grace period ends.

Thus, rcu_gp_might_be_stalled() can be used to help decide whether
allocating memory on an RCU free path is a semi-reasonable course
of action.

Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
a6a82ce18b rcu/tree: Count number of batched kfree_rcu() locklessly
We can relax the correctness of counting of number of queued objects in
favor of not hurting performance, by locklessly sampling per-cpu
counters. This should be Ok since under high memory pressure, it should not
matter if we are off by a few objects while counting. The shrinker will
still do the reclaim.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ paulmck: Remove unused "flags" variable. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
9154244c1a rcu/tree: Add a shrinker to prevent OOM due to kfree_rcu() batching
To reduce grace periods and improve kfree() performance, we have done
batching recently dramatically bringing down the number of grace periods
while giving us the ability to use kfree_bulk() for efficient kfree'ing.

However, this has increased the likelihood of OOM condition under heavy
kfree_rcu() flood on small memory systems. This patch introduces a
shrinker which starts grace periods right away if the system is under
memory pressure due to existence of objects that have still not started
a grace period.

With this patch, I do not observe an OOM anymore on a system with 512MB
RAM and 8 CPUs, with the following rcuperf options:

rcuperf.kfree_loops=20000 rcuperf.kfree_alloc_num=8000
rcuperf.kfree_rcu_test=1 rcuperf.kfree_mult=2

Otherwise it easily OOMs with the above parameters.

NOTE:
1. On systems with no memory pressure, the patch has no effect as intended.
2. In the future, we can use this same mechanism to prevent grace periods
   from happening even more, by relying on shrinkers carefully.

Cc: urezki@gmail.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
f87dc80800 rcuperf: Add ability to increase object allocation size
This allows us to increase memory pressure dynamically using a new
rcuperf boot command line parameter called 'rcumult'.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Paul E. McKenney
e2f3ccfa62 rcu: Convert rcu_nohz_full_cpu() ULONG_CMP_LT() to time_before()
This commit converts the ULONG_CMP_LT() in rcu_nohz_full_cpu() to
time_before() to reflect the fact that it is comparing a timestamp to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:17 -07:00
Paul E. McKenney
7b2413111a rcu: Convert rcu_initiate_boost() ULONG_CMP_GE() to time_after()
This commit converts the ULONG_CMP_GE() in rcu_initiate_boost() to
time_after() to reflect the fact that it is comparing a timestamp to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00