Pull timer fix from Thomas Gleixner:
"A one-liner fix which prevents deferrable timers becoming stale when
the system does not switch into NOHZ mode"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers: Unconditionally check deferrable base
Pull networking fixes from David Miller:
1) Two read past end of buffer fixes in AF_KEY, from Eric Biggers.
2) Memory leak in key_notify_policy(), from Steffen Klassert.
3) Fix overflow with bpf arrays, from Daniel Borkmann.
4) Fix RDMA regression with mlx5 due to mlx5 no longer using
pci_irq_get_affinity(), from Saeed Mahameed.
5) Missing RCU read locking in nl80211_send_iface() when it calls
ieee80211_bss_get_ie(), from Dominik Brodowski.
6) cfg80211 should check dev_set_name()'s return value, from Johannes
Berg.
7) Missing module license tag in 9p protocol, from Stephen Hemminger.
8) Fix crash due to too small MTU in udp ipv6 sendmsg, from Mike
Maloney.
9) Fix endless loop in netlink extack code, from David Ahern.
10) TLS socket layer sets inverted error codes, resulting in an endless
loop. From Robert Hering.
11) Revert openvswitch erspan tunnel support, it's mis-designed and we
need to kill it before it goes into a real release. From William Tu.
12) Fix lan78xx failures in full speed USB mode, from Yuiko Oshino.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits)
net, sched: fix panic when updating miniq {b,q}stats
qed: Fix potential use-after-free in qed_spq_post()
nfp: use the correct index for link speed table
lan78xx: Fix failure in USB Full Speed
sctp: do not allow the v4 socket to bind a v4mapped v6 address
sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf
sctp: reinit stream if stream outcnt has been change by sinit in sendmsg
ibmvnic: Fix pending MAC address changes
netlink: extack: avoid parenthesized string constant warning
ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY
net: Allow neigh contructor functions ability to modify the primary_key
sh_eth: fix dumping ARSTR
Revert "openvswitch: Add erspan tunnel support."
net/tls: Fix inverted error codes to avoid endless loop
ipv6: ip6_make_skb() needs to clear cork.base.dst
sctp: avoid compiler warning on implicit fallthru
net: ipv4: Make "ip route get" match iif lo rules again.
netlink: extack needs to be reset each time through loop
tipc: fix a memory leak in tipc_nl_node_get_link()
ipv6: fix udpv6 sendmsg crash caused by too small MTU
...
- Bring back context level recursive protection in ring buffer.
The simpler counter protection failed, due to a path when
tracing with trace_clock_global() as it could not be reentrant
and depended on the ring buffer recursive protection to keep that
from happening.
- Prevent branch profiling when FORTIFY_SOURCE is enabled. It causes
50 - 60 MB in warning messages. Branch profiling should never be
run on production systems, so there's no reason that it needs to
be enabled with FORTIFY_SOURCE.
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Merge tag 'trace-v4.15-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Bring back context level recursive protection in ring buffer.
The simpler counter protection failed, due to a path when tracing
with trace_clock_global() as it could not be reentrant and depended
on the ring buffer recursive protection to keep that from happening.
- Prevent branch profiling when FORTIFY_SOURCE is enabled.
It causes 50 - 60 MB in warning messages. Branch profiling should
never be run on production systems, so there's no reason that it
needs to be enabled with FORTIFY_SOURCE.
* tag 'trace-v4.15-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Prevent PROFILE_ALL_BRANCHES when FORTIFY_SOURCE=y
ring-buffer: Bring back context level recursive checks
I regularly get 50 MB - 60 MB files during kernel randconfig builds.
These large files mostly contain (many repeats of; e.g., 124,594):
In file included from ../include/linux/string.h:6:0,
from ../include/linux/uuid.h:20,
from ../include/linux/mod_devicetable.h:13,
from ../scripts/mod/devicetable-offsets.c:3:
../include/linux/compiler.h:64:4: warning: '______f' is static but declared in inline function 'strcpy' which is not static [enabled by default]
______f = { \
^
../include/linux/compiler.h:56:23: note: in expansion of macro '__trace_if'
^
../include/linux/string.h:425:2: note: in expansion of macro 'if'
if (p_size == (size_t)-1 && q_size == (size_t)-1)
^
This only happens when CONFIG_FORTIFY_SOURCE=y and
CONFIG_PROFILE_ALL_BRANCHES=y, so prevent PROFILE_ALL_BRANCHES if
FORTIFY_SOURCE=y.
Link: http://lkml.kernel.org/r/9199446b-a141-c0c3-9678-a3f9107f2750@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Commit 1a149d7d3f ("ring-buffer: Rewrite trace_recursive_(un)lock() to be
simpler") replaced the context level recursion checks with a simple counter.
This would prevent the ring buffer code from recursively calling itself more
than the max number of contexts that exist (Normal, softirq, irq, nmi). But
this change caused a lockup in a specific case, which was during suspend and
resume using a global clock. Adding a stack dump to see where this occurred,
the issue was in the trace global clock itself:
trace_buffer_lock_reserve+0x1c/0x50
__trace_graph_entry+0x2d/0x90
trace_graph_entry+0xe8/0x200
prepare_ftrace_return+0x69/0xc0
ftrace_graph_caller+0x78/0xa8
queued_spin_lock_slowpath+0x5/0x1d0
trace_clock_global+0xb0/0xc0
ring_buffer_lock_reserve+0xf9/0x390
The function graph tracer traced queued_spin_lock_slowpath that was called
by trace_clock_global. This pointed out that the trace_clock_global() is not
reentrant, as it takes a spin lock. It depended on the ring buffer recursive
lock from letting that happen.
By removing the context detection and adding just a max number of allowable
recursions, it allowed the trace_clock_global() to be entered again and try
to retake the spinlock it already held, causing a deadlock.
Fixes: 1a149d7d3f ("ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler")
Reported-by: David Weinehall <david.weinehall@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When the timer base is checked for expired timers then the deferrable base
must be checked as well. This was missed when making the deferrable base
independent of base::nohz_active.
Fixes: ced6d5c11d ("timers: Use deferrable base independent of base::nohz_active")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
Julia reported futex state corruption in the following scenario:
waiter waker stealer (prio > waiter)
futex(WAIT_REQUEUE_PI, uaddr, uaddr2,
timeout=[N ms])
futex_wait_requeue_pi()
futex_wait_queue_me()
freezable_schedule()
<scheduled out>
futex(LOCK_PI, uaddr2)
futex(CMP_REQUEUE_PI, uaddr,
uaddr2, 1, 0)
/* requeues waiter to uaddr2 */
futex(UNLOCK_PI, uaddr2)
wake_futex_pi()
cmp_futex_value_locked(uaddr2, waiter)
wake_up_q()
<woken by waker>
<hrtimer_wakeup() fires,
clears sleeper->task>
futex(LOCK_PI, uaddr2)
__rt_mutex_start_proxy_lock()
try_to_take_rt_mutex() /* steals lock */
rt_mutex_set_owner(lock, stealer)
<preempted>
<scheduled in>
rt_mutex_wait_proxy_lock()
__rt_mutex_slowlock()
try_to_take_rt_mutex() /* fails, lock held by stealer */
if (timeout && !timeout->task)
return -ETIMEDOUT;
fixup_owner()
/* lock wasn't acquired, so,
fixup_pi_state_owner skipped */
return -ETIMEDOUT;
/* At this point, we've returned -ETIMEDOUT to userspace, but the
* futex word shows waiter to be the owner, and the pi_mutex has
* stealer as the owner */
futex_lock(LOCK_PI, uaddr2)
-> bails with EDEADLK, futex word says we're owner.
And suggested that what commit:
73d786bd04 ("futex: Rework inconsistent rt_mutex/futex_q state")
removes from fixup_owner() looks to be just what is needed. And indeed
it is -- I completely missed that requeue_pi could also result in this
case. So we need to restore that, except that subsequent patches, like
commit:
16ffa12d74 ("futex: Pull rt_mutex_futex_unlock() out from under hb->lock")
changed all the locking rules. Even without that, the sequence:
- if (rt_mutex_futex_trylock(&q->pi_state->pi_mutex)) {
- locked = 1;
- goto out;
- }
- raw_spin_lock_irq(&q->pi_state->pi_mutex.wait_lock);
- owner = rt_mutex_owner(&q->pi_state->pi_mutex);
- if (!owner)
- owner = rt_mutex_next_owner(&q->pi_state->pi_mutex);
- raw_spin_unlock_irq(&q->pi_state->pi_mutex.wait_lock);
- ret = fixup_pi_state_owner(uaddr, q, owner);
already suggests there were races; otherwise we'd never have to look
at next_owner.
So instead of doing 3 consecutive wait_lock sections with who knows
what races, we do it all in a single section. Additionally, the usage
of pi_state->owner in fixup_owner() was only safe because only the
rt_mutex owner would modify it, which this additional case wrecks.
Luckily the values can only change away and not to the value we're
testing, this means we can do a speculative test and double check once
we have the wait_lock.
Fixes: 73d786bd04 ("futex: Rework inconsistent rt_mutex/futex_q state")
Reported-by: Julia Cartwright <julia@ni.com>
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Julia Cartwright <julia@ni.com>
Tested-by: Gratian Crisan <gratian.crisan@ni.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20171208124939.7livp7no2ov65rrc@hirez.programming.kicks-ass.net
Merge misc fixlets from Andrew Morton:
"4 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
tools/objtool/Makefile: don't assume sync-check.sh is executable
kdump: write correct address of mem_section into vmcoreinfo
kmemleak: allow to coexist with fault injection
MAINTAINERS, nilfs2: change project home URLs
Depending on configuration mem_section can now be an array or a pointer
to an array allocated dynamically. In most cases, we can continue to
refer to it as 'mem_section' regardless of what it is.
But there's one exception: '&mem_section' means "address of the array"
if mem_section is an array, but if mem_section is a pointer, it would
mean "address of the pointer".
We've stepped onto this in kdump code. VMCOREINFO_SYMBOL(mem_section)
writes down address of pointer into vmcoreinfo, not array as we wanted.
Let's introduce VMCOREINFO_SYMBOL_ARRAY() that would handle the
situation correctly for both cases.
Link: http://lkml.kernel.org/r/20180112162532.35896-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull scheduler fixes from Ingo Molnar:
"A Kconfig fix, a build fix and a membarrier bug fix"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
membarrier: Disable preemption when calling smp_call_function_many()
sched/isolation: Make CONFIG_CPU_ISOLATION=y depend on SMP or COMPILE_TEST
ia64, sched/cputime: Fix build error if CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y
Pull locking fixes from Ingo Molnar:
"No functional effects intended: removes leftovers from recent lockdep
and refcounts work"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/refcounts: Remove stale comment from the ARCH_HAS_REFCOUNT Kconfig entry
locking/lockdep: Remove cross-release leftovers
locking/Documentation: Remove stale crossrelease_fullstack parameter
syzkaller tried to alloc a map with 0xfffffffd entries out of a userns,
and thus unprivileged. With the recently added logic in b2157399cc
("bpf: prevent out-of-bounds speculation") we round this up to the next
power of two value for max_entries for unprivileged such that we can
apply proper masking into potentially zeroed out map slots.
However, this will generate an index_mask of 0xffffffff, and therefore
a + 1 will let this overflow into new max_entries of 0. This will pass
allocation, etc, and later on map access we still enforce on the original
attr->max_entries value which was 0xfffffffd, therefore triggering GPF
all over the place. Thus bail out on overflow in such case.
Moreover, on 32 bit archs roundup_pow_of_two() can also not be used,
since fls_long(max_entries - 1) can result in 32 and 1UL << 32 in 32 bit
space is undefined. Therefore, do this by hand in a 64 bit variable.
This fixes all the issues triggered by syzkaller's reproducers.
Fixes: b2157399cc ("bpf: prevent out-of-bounds speculation")
Reported-by: syzbot+b0efb8e572d01bce1ae0@syzkaller.appspotmail.com
Reported-by: syzbot+6c15e9744f75f2364773@syzkaller.appspotmail.com
Reported-by: syzbot+d2f5524fb46fd3b312ee@syzkaller.appspotmail.com
Reported-by: syzbot+61d23c95395cc90dbc2b@syzkaller.appspotmail.com
Reported-by: syzbot+0d363c942452cca68c01@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The following snippet was throwing an 'unknown opcode cc' warning
in BPF interpreter:
0: (18) r0 = 0x0
2: (7b) *(u64 *)(r10 -16) = r0
3: (cc) (u32) r0 s>>= (u32) r0
4: (95) exit
Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
generation, not all of them do and interpreter does neither. We can
leave existing ones and implement it later in bpf-next for the
remaining ones, but reject this properly in verifier for the time
being.
Fixes: 17a5267067 ("bpf: verifier (add verifier core)")
Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Trivial fix to spelling mistake in error message text.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf 2018-01-09
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Prevent out-of-bounds speculation in BPF maps by masking the
index after bounds checks in order to fix spectre v1, and
add an option BPF_JIT_ALWAYS_ON into Kconfig that allows for
removing the BPF interpreter from the kernel in favor of
JIT-only mode to make spectre v2 harder, from Alexei.
2) Remove false sharing of map refcount with max_entries which
was used in spectre v1, from Daniel.
3) Add a missing NULL psock check in sockmap in order to fix
a race, from John.
4) Fix test_align BPF selftest case since a recent change in
verifier rejects the bit-wise arithmetic on pointers
earlier but test_align update was missing, from Alexei.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
smp_call_function_many() requires disabling preemption around the call.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: <stable@vger.kernel.org> # v4.14+
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Andrew Hunter <ahh@google.com>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maged Michael <maged.michael@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171215192310.25293-1-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715.
A quote from goolge project zero blog:
"At this point, it would normally be necessary to locate gadgets in
the host kernel code that can be used to actually leak data by reading
from an attacker-controlled location, shifting and masking the result
appropriately and then using the result of that as offset to an
attacker-controlled address for a load. But piecing gadgets together
and figuring out which ones work in a speculation context seems annoying.
So instead, we decided to use the eBPF interpreter, which is built into
the host kernel - while there is no legitimate way to invoke it from inside
a VM, the presence of the code in the host kernel's text section is sufficient
to make it usable for the attack, just like with ordinary ROP gadgets."
To make attacker job harder introduce BPF_JIT_ALWAYS_ON config
option that removes interpreter from the kernel in favor of JIT-only mode.
So far eBPF JIT is supported by:
x64, arm64, arm32, sparc64, s390, powerpc64, mips64
The start of JITed program is randomized and code page is marked as read-only.
In addition "constant blinding" can be turned on with net.core.bpf_jit_harden
v2->v3:
- move __bpf_prog_ret0 under ifdef (Daniel)
v1->v2:
- fix init order, test_bpf and cBPF (Daniel's feedback)
- fix offloaded bpf (Jakub's feedback)
- add 'return 0' dummy in case something can invoke prog->bpf_func
- retarget bpf tree. For bpf-next the patch would need one extra hunk.
It will be sent when the trees are merged back to net-next
Considered doing:
int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT;
but it seems better to land the patch as-is and in bpf-next remove
bpf_jit_enable global variable from all JITs, consolidate in one place
and remove this jit_init() function.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Under speculation, CPUs may mis-predict branches in bounds checks. Thus,
memory accesses under a bounds check may be speculated even if the
bounds check fails, providing a primitive for building a side channel.
To avoid leaking kernel data round up array-based maps and mask the index
after bounds check, so speculated load with out of bounds index will load
either valid value from the array or zero from the padded area.
Unconditionally mask index for all array types even when max_entries
are not rounded to power of 2 for root user.
When map is created by unpriv user generate a sequence of bpf insns
that includes AND operation to make sure that JITed code includes
the same 'index & index_mask' operation.
If prog_array map is created by unpriv user replace
bpf_tail_call(ctx, map, index);
with
if (index >= max_entries) {
index &= map->index_mask;
bpf_tail_call(ctx, map, index);
}
(along with roundup to power 2) to prevent out-of-bounds speculation.
There is secondary redundant 'if (index >= max_entries)' in the interpreter
and in all JITs, but they can be optimized later if necessary.
Other array-like maps (cpumap, devmap, sockmap, perf_event_array, cgroup_array)
cannot be used by unpriv, so no changes there.
That fixes bpf side of "Variant 1: bounds check bypass (CVE-2017-5753)" on
all architectures with and without JIT.
v2->v3:
Daniel noticed that attack potentially can be crafted via syscall commands
without loading the program, so add masking to those paths as well.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Pull cgroup fixes from Tejun Heo:
"This contains fixes for the following two non-trivial issues:
- The task iterator got broken while adding thread mode support for
v4.14. It was less visible because it only triggers when both
cgroup1 and cgroup2 hierarchies are in use. The recent versions of
systemd uses cgroup2 for process management even when cgroup1 is
used for resource control exposing this issue.
- cpuset CPU hotplug path could deadlock when racing against exits.
There also are two patches to replace unlimited strcpy() usages with
strlcpy()"
* 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix css_task_iter crash on CSS_TASK_ITER_PROC
cgroup: Fix deadlock in cpu hotplug path
cgroup: use strlcpy() instead of strscpy() to avoid spurious warning
cgroup: avoid copying strings longer than the buffers
Pull vfs fixes from Al Viro:
- untangle sys_close() abuses in xt_bpf
- deal with register_shrinker() failures in sget()
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix "netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'"
sget(): handle failures of register_shrinker()
mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed.
Add psock NULL check to handle a racing sock event that can get the
sk_callback_lock before this case but after xchg happens causing the
refcnt to hit zero and sock user data (psock) to be null and queued
for garbage collection.
Also add a comment in the code because this is a bit subtle and
not obvious in my opinion.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Descriptor table is a shared object; it's not a place where you can
stick temporary references to files, especially when we don't need
an opened file at all.
Cc: stable@vger.kernel.org # v4.14
Fixes: 98589a0998 ("netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As Tsukada explains, the time_is_before_jiffies(acct->needcheck) check
is very wrong, we need time_is_after_jiffies() to make sys_acct() work.
Ignoring the overflows, the code should "goto out" if needcheck >
jiffies, while currently it checks "needcheck < jiffies" and thus in the
likely case check_free_space() does nothing until jiffies overflow.
In particular this means that sys_acct() is simply broken, acct_on()
sets acct->needcheck = jiffies and expects that check_free_space()
should set acct->active = 1 after the free-space check, but this won't
happen if jiffies increments in between.
This was broken by commit 32dc730860 ("get rid of timer in
kern/acct.c") in 2011, then another (correct) commit 795a2f22a8
("acct() should honour the limits from the very beginning") made the
problem more visible.
Link: http://lkml.kernel.org/r/20171213133940.GA6554@redhat.com
Fixes: 32dc730860 ("get rid of timer in kern/acct.c")
Reported-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
Suggested-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull pid allocation bug fix from Eric Biederman:
"The replacement of the pid hash table and the pid bitmap with an idr
resulted in an implementation that now fails more often in low memory
situations. Allowing fuzzers to observe bad behavior from a memory
allocation failure during pid allocation.
This is a small change to fix this by making the kernel more robust in
the case of error. The non-error paths are left alone so the only
danger is to the already broken error path. I have manually injected
errors and verified that this new error handling works"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
pid: Handle failure to allocate the first pid in a pid namespace
Pull timer fixes from Thomas Gleixner:
"A pile of fixes for long standing issues with the timer wheel and the
NOHZ code:
- Prevent timer base confusion accross the nohz switch, which can
cause unlocked access and data corruption
- Reinitialize the stale base clock on cpu hotplug to prevent subtle
side effects including rollovers on 32bit
- Prevent an interrupt storm when the timer softirq is already
pending caused by tick_nohz_stop_sched_tick()
- Move the timer start tracepoint to a place where it actually makes
sense
- Add documentation to timerqueue functions as they caused confusion
several times now"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timerqueue: Document return values of timerqueue_add/del()
timers: Invoke timer_start_debug() where it makes sense
nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()
timers: Reinitialize per cpu bases on hotplug
timers: Use deferrable base independent of base::nohz_active
Pull smp fixlet from Thomas Gleixner:
"A trivial build warning fix for newer compilers"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Move inline keyword at the beginning of declaration
Pull scheduler fixes from Thomas Gleixner:
"Three patches addressing the fallout of the CPU_ISOLATION changes
especially with NO_HZ_FULL plus documentation of boot parameter
dependency"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/isolation: Document boot parameters dependency on CONFIG_CPU_ISOLATION=y
sched/isolation: Enable CONFIG_CPU_ISOLATION=y by default
sched/isolation: Make CONFIG_NO_HZ_FULL select CONFIG_CPU_ISOLATION
Pull irq fixes from Thomas Gleixner:
"A rather large update after the kaisered maintainer finally found time
to handle regression reports.
- The larger part addresses a regression caused by the x86 vector
management rework.
The reservation based model does not work reliably for MSI
interrupts, if they cannot be masked (yes, yet another hw
engineering trainwreck). The reason is that the reservation mode
assigns a dummy vector when the interrupt is allocated and switches
to a real vector when the interrupt is requested.
If the MSI entry cannot be masked then the initialization might
raise an interrupt before the interrupt is requested, which ends up
as spurious interrupt and causes device malfunction and worse. The
fix is to exclude MSI interrupts which do not support masking from
reservation mode and assign a real vector right away.
- Extend the extra lockdep class setup for nested interrupts with a
class for the recently added irq_desc::request_mutex so lockdep can
differeniate and does not emit false positive warnings.
- A ratelimit guard for the bad irq printout so in case a bad irq
comes back immediately the system does not drown in dmesg spam"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/msi, x86/vector: Prevent reservation mode for non maskable MSI
genirq/irqdomain: Rename early argument of irq_domain_activate_irq()
x86/vector: Use IRQD_CAN_RESERVE flag
genirq: Introduce IRQD_CAN_RESERVE flag
genirq/msi: Handle reactivation only on success
gpio: brcmstb: Make really use of the new lockdep class
genirq: Guard handle_bad_irq log messages
kernel/irq: Extend lockdep class for request mutex
The timer start debug function is called before the proper timer base is
set. As a consequence the trace data contains the stale CPU and flags
values.
Call the debug function after setting the new base and flags.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Link: https://lkml.kernel.org/r/20171222145337.792907137@linutronix.de
The conditions in irq_exit() to invoke tick_nohz_irq_exit() which
subsequently invokes tick_nohz_stop_sched_tick() are:
if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu))
If need_resched() is not set, but a timer softirq is pending then this is
an indication that the softirq code punted and delegated the execution to
softirqd. need_resched() is not true because the current interrupted task
takes precedence over softirqd.
Invoking tick_nohz_irq_exit() in this case can cause an endless loop of
timer interrupts because the timer wheel contains an expired timer, but
softirqs are not yet executed. So it returns an immediate expiry request,
which causes the timer to fire immediately again. Lather, rinse and
repeat....
Prevent that by adding a check for a pending timer soft interrupt to the
conditions in tick_nohz_stop_sched_tick() which avoid calling
get_next_timer_interrupt(). That keeps the tick sched timer on the tick and
prevents a repetitive programming of an already expired timer.
Reported-by: Sebastian Siewior <bigeasy@linutronix.d>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272156050.2431@nanos
The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.
Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.
Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos
During boot and before base::nohz_active is set in the timer bases, deferrable
timers are enqueued into the standard timer base. This works correctly as
long as base::nohz_active is false.
Once it base::nohz_active is set and a timer which was enqueued before that
is accessed the lock selector code choses the lock of the deferred
base. This causes unlocked access to the standard base and in case the
timer is removed it does not clear the pending flag in the standard base
bitmap which causes get_next_timer_interrupt() to return bogus values.
To prevent that, the deferrable timers must be enqueued in the deferrable
base, even when base::nohz_active is not set. Those deferrable timers also
need to be expired unconditional.
Fixes: 500462a9de ("timers: Switch to a non-cascading wheel")
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20171222145337.633328378@linutronix.de
The new reservation mode for interrupts assigns a dummy vector when the
interrupt is allocated and assigns a real vector when the interrupt is
requested. The reservation mode prevents vector pressure when devices with
a large amount of queues/interrupts are initialized, but only a minimal
subset of those queues/interrupts is actually used.
This mode has an issue with MSI interrupts which cannot be masked. If the
driver is not careful or the hardware emits an interrupt before the device
irq is requestd by the driver then the interrupt ends up on the dummy
vector as a spurious interrupt which can cause malfunction of the device or
in the worst case a lockup of the machine.
Change the logic for the reservation mode so that the early activation of
MSI interrupts checks whether:
- the device is a PCI/MSI device
- the reservation mode of the underlying irqdomain is activated
- PCI/MSI masking is globally enabled
- the PCI/MSI device uses either MSI-X, which supports masking, or
MSI with the maskbit supported.
If one of those conditions is false, then clear the reservation mode flag
in the irq data of the interrupt and invoke irq_domain_activate_irq() with
the reserve argument cleared. In the x86 vector code, clear the can_reserve
flag in the vector allocation data so a subsequent free_irq() won't create
the same situation again. The interrupt stays assigned to a real vector
until pci_disable_msi() is invoked and all allocations are undone.
Fixes: 4900be8360 ("x86/vector/msi: Switch to global reservation mode")
Reported-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712291406420.1899@nanos
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712291409460.1899@nanos
The 'early' argument of irq_domain_activate_irq() is actually used to
denote reservation mode. To avoid confusion, rename it before abuse
happens.
No functional change.
Fixes: 7249164346 ("genirq/irqdomain: Update irq_domain_ops.activate() signature")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexandru Chirvasitu <achirvasub@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
Add a new flag to mark interrupts which can use reservation mode. This is
going to be used in subsequent patches to disable reservation mode for a
certain class of MSI devices.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
When analyzing the fallout of the x86 vector allocation rework it turned
out that the error handling in msi_domain_alloc_irqs() is broken.
If MSI_FLAG_MUST_REACTIVATE is set for a MSI domain then it clears the
activation flag for a successfully initialized msi descriptor. If a
subsequent initialization fails then the error handling code path does not
deactivate the interrupt because the activation flag got cleared.
Move the clearing of the activation flag outside of the initialization loop
so that an eventual failure can be cleaned up correctly.
Fixes: 22d0b12f35 ("genirq/irqdomain: Add force reactivation flag to irq domains")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Mikael Pettersson <mikpelinux@gmail.com>
Cc: Josh Poulson <jopoulso@microsoft.com>
Cc: Mihai Costache <v-micos@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Simon Xiao <sixiao@microsoft.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Jork Loeser <Jork.Loeser@microsoft.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: devel@linuxdriverproject.org
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Sakari Ailus <sakari.ailus@intel.com>,
Cc: linux-media@vger.kernel.org
This fixes a schedutil cpufreq governor regression from the 4.14
cycle that may cause a CPU idleness check to return incorrect results
in some cases which leads to suboptimal decisions (Joel Fernandes).
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Merge tag 'pm-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fix from Rafael Wysocki:
"This fixes a schedutil cpufreq governor regression from the 4.14 cycle
that may cause a CPU idleness check to return incorrect results in
some cases which leads to suboptimal decisions (Joel Fernandes)"
* tag 'pm-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: schedutil: Use idle_calls counter of the remote CPU
An interrupt storm on a bad interrupt will cause the kernel
log to be clogged.
[ 60.089234] ->handle_irq(): ffffffffbe2f803f,
[ 60.090455] 0xffffffffbf2af380
[ 60.090510] handle_bad_irq+0x0/0x2e5
[ 60.090522] ->irq_data.chip(): ffffffffbf2af380,
[ 60.090553] IRQ_NOPROBE set
[ 60.090584] ->handle_irq(): ffffffffbe2f803f,
[ 60.090590] handle_bad_irq+0x0/0x2e5
[ 60.090596] ->irq_data.chip(): ffffffffbf2af380,
[ 60.090602] 0xffffffffbf2af380
[ 60.090608] ->action(): (null)
[ 60.090779] handle_bad_irq+0x0/0x2e5
This was seen when running an upstream kernel on Acer Chromebook R11. The
system was unstable as result.
Guard the log message with __printk_ratelimit to reduce the impact. This
won't prevent the interrupt storm from happening, but at least the system
remains stable.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dtor@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197953
Link: https://lkml.kernel.org/r/1512234784-21038-1-git-send-email-linux@roeck-us.net
Since the recent remote cpufreq callback work, its possible that a cpufreq
update is triggered from a remote CPU. For single policies however, the current
code uses the local CPU when trying to determine if the remote sg_cpu entered
idle or is busy. This is incorrect. To remedy this, compare with the nohz tick
idle_calls counter of the remote CPU.
Fixes: 674e75411f (sched: cpufreq: Allow remote cpufreq callbacks)
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Joel Fernandes <joelaf@google.com>
Cc: 4.14+ <stable@vger.kernel.org> # 4.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
were getting corrupted. In the process I found three bugs. One was the
culprit, but the other two scared me. After deeper investigation, they
were not as major as I thought they were, due to a signed compared to
an unsigned that prevented a negative number from doing actual harm.
The two bigger bugs:
- Mask the ring buffer data page length. There are data flags at the
high bits of the length field. These were not cleared via the
length function, and the length could return a negative number.
(Although the number returned was unsigned, but was assigned to a
signed number) Luckily, this value was compared to PAGE_SIZE which is
unsigned and kept it from entering the path that could have caused damage.
- Check the page usage before reusing the ring buffer reader page.
TCP increments the page ref when passing the page off to the network.
The page is passed back to the ring buffer for use on free. But
the page could still be in use by the TCP stack.
Minor bugs:
- Related to the first bug. No need to clear out the unused ring buffer
data before sending to user space. It is now done by the ring buffer
code itself.
- Reset pointers after free on error path. There were some cases in
the error path that pointers were freed but not set to NULL, and could
have them freed again, having a pointer freed twice.
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Merge tag 'trace-v4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"While doing tests on tracing over the network, I found that the
packets were getting corrupted.
In the process I found three bugs.
One was the culprit, but the other two scared me. After deeper
investigation, they were not as major as I thought they were, due to a
signed compared to an unsigned that prevented a negative number from
doing actual harm.
The two bigger bugs:
- Mask the ring buffer data page length. There are data flags at the
high bits of the length field. These were not cleared via the
length function, and the length could return a negative number.
(Although the number returned was unsigned, but was assigned to a
signed number) Luckily, this value was compared to PAGE_SIZE which
is unsigned and kept it from entering the path that could have
caused damage.
- Check the page usage before reusing the ring buffer reader page.
TCP increments the page ref when passing the page off to the
network. The page is passed back to the ring buffer for use on
free. But the page could still be in use by the TCP stack.
Minor bugs:
- Related to the first bug. No need to clear out the unused ring
buffer data before sending to user space. It is now done by the
ring buffer code itself.
- Reset pointers after free on error path. There were some cases in
the error path that pointers were freed but not set to NULL, and
could have them freed again, having a pointer freed twice"
* tag 'trace-v4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix possible double free on failure of allocating trace buffer
tracing: Fix crash when it fails to alloc ring buffer
ring-buffer: Do no reuse reader page if still in use
tracing: Remove extra zeroing out of the ring buffer page
ring-buffer: Mask out the info bits when returning buffer page length
Jing Xia and Chunyan Zhang reported that on failing to allocate part of the
tracing buffer, memory is freed, but the pointers that point to them are not
initialized back to NULL, and later paths may try to free the freed memory
again. Jing and Chunyan fixed one of the locations that does this, but
missed a spot.
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Cc: stable@vger.kernel.org
Fixes: 737223fbca ("tracing: Consolidate buffer allocation code")
Reported-by: Jing Xia <jing.xia@spreadtrum.com>
Reported-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Double free of the ring buffer happens when it fails to alloc new
ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured.
The root cause is that the pointer is not set to NULL after the buffer
is freed in allocate_trace_buffers(), and the freeing of the ring
buffer is invoked again later if the pointer is not equal to Null,
as:
instance_mkdir()
|-allocate_trace_buffers()
|-allocate_trace_buffer(tr, &tr->trace_buffer...)
|-allocate_trace_buffer(tr, &tr->max_buffer...)
// allocate fail(-ENOMEM),first free
// and the buffer pointer is not set to null
|-ring_buffer_free(tr->trace_buffer.buffer)
// out_free_tr
|-free_trace_buffers()
|-free_trace_buffer(&tr->trace_buffer);
//if trace_buffer is not null, free again
|-ring_buffer_free(buf->buffer)
|-rb_free_cpu_buffer(buffer->buffers[cpu])
// ring_buffer_per_cpu is null, and
// crash in ring_buffer_per_cpu->pages
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Cc: stable@vger.kernel.org
Fixes: 737223fbca ("tracing: Consolidate buffer allocation code")
Signed-off-by: Jing Xia <jing.xia@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
To free the reader page that is allocated with ring_buffer_alloc_read_page(),
ring_buffer_free_read_page() must be called. For faster performance, this
page can be reused by the ring buffer to avoid having to free and allocate
new pages.
The issue arises when the page is used with a splice pipe into the
networking code. The networking code may up the page counter for the page,
and keep it active while sending it is queued to go to the network. The
incrementing of the page ref does not prevent it from being reused in the
ring buffer, and this can cause the page that is being sent out to the
network to be modified before it is sent by reading new data.
Add a check to the page ref counter, and only reuse the page if it is not
being used anywhere else.
Cc: stable@vger.kernel.org
Fixes: 73a757e631 ("ring-buffer: Return reader page back into existing ring buffer")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The ring_buffer_read_page() takes care of zeroing out any extra data in the
page that it returns. There's no need to zero it out again from the
consumer. It was removed from one consumer of this function, but
read_buffers_splice_read() did not remove it, and worse, it contained a
nasty bug because of it.
Cc: stable@vger.kernel.org
Fixes: 2711ca237a ("ring-buffer: Move zeroing out excess in page to ring buffer code")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Two info bits were added to the "commit" part of the ring buffer data page
when returned to be consumed. This was to inform the user space readers that
events have been missed, and that the count may be stored at the end of the
page.
What wasn't handled, was the splice code that actually called a function to
return the length of the data in order to zero out the rest of the page
before sending it up to user space. These data bits were returned with the
length making the value negative, and that negative value was not checked.
It was compared to PAGE_SIZE, and only used if the size was less than
PAGE_SIZE. Luckily PAGE_SIZE is unsigned long which made the compare an
unsigned compare, meaning the negative size value did not end up causing a
large portion of memory to be randomly zeroed out.
Cc: stable@vger.kernel.org
Fixes: 66a8cb95ed ("ring-buffer: Add place holder recording of dropped events")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
