Commit Graph

1125 Commits

Author SHA1 Message Date
Linus Torvalds
f3033eb791 - Core Frameworks
- Ensure seldom updated triggers have a brightness value before first update
 
  - New Device Support
    - Add support for Simatic IPC Device BX_59A to IPC LEDs Core
    - Add support for Qualcomm PMI8950 PWM to LPG Core
 
  - New Functionality
    - Add a bunch of new LED function identifiers
    - Add support for High Resolution Timers in LED Trigger Patten
 
  - Fix-ups
    - Shift out Audio Trigger to the Sound subsystem
    - Convert suitable calls to devm_* managed resources
    - Device Tree binding adaptions/conversions/creation
    - Remove superfluous code/variables/attributes and simplify overall
    - Use/convert to new/better APIs/helpers/MACROs instead of hand-rolling implementations
 
  - Bug Fixes
    - Repair enabling Torch Mode from V4L2 on the second LED
    - Ensure PWM is disabled when suspending
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Merge tag 'leds-next-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds

Pull LED updates from Lee Jones:
 "Core Frameworks:
   - Ensure seldom updated triggers have a brightness value before first
     update

  New Device Support:
   - Add support for Simatic IPC Device BX_59A to IPC LEDs Core
   - Add support for Qualcomm PMI8950 PWM to LPG Core

  New Functionality:
   - Add a bunch of new LED function identifiers
   - Add support for High Resolution Timers in LED Trigger Patten

  Fix-ups:
   - Shift out Audio Trigger to the Sound subsystem
   - Convert suitable calls to devm_* managed resources
   - Device Tree binding adaptions/conversions/creation
   - Remove superfluous code/variables/attributes and simplify overall
   - Use/convert to new/better APIs/helpers/MACROs instead of
     hand-rolling implementations

  Bug Fixes:
   - Repair enabling Torch Mode from V4L2 on the second LED
   - Ensure PWM is disabled when suspending"

* tag 'leds-next-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds: (28 commits)
  leds: mt6370: Remove unused field 'reg_cfgs' from 'struct mt6370_priv'
  leds: lp50xx: Remove unused field 'num_of_banked_leds' from 'struct lp50xx'
  leds: lp50xx: Remove unused field 'bank_modules' from 'struct lp50xx_led'
  leds: aat1290: Remove unused field 'torch_brightness' from 'struct aat1290_led'
  leds: sun50i-a100: Use match_string() helper to simplify the code
  leds: pwm: Disable PWM when going to suspend
  leds: trigger: pattern: Add support for hrtimer
  leds: mt6360: Fix the second LED can not enable torch mode by V4L2
  dt-bindings: leds: leds-qcom-lpg: Add support for PMI8950 PWM
  leds: qcom-lpg: Add support for PMI8950 PWM
  leds: apu: Remove duplicate DMI lookup data
  leds: trigger: netdev: Remove not needed call to led_set_brightness in deactivate
  dt-bindings: leds: Add LED_FUNCTION_SPEED_* for link speed on LAN/WAN
  dt-bindings: leds: Add LED_FUNCTION_MOBILE for mobile network
  leds: simatic-ipc-leds-gpio: Add support for module BX-59A
  dt-bindings: leds: qcom-lpg: Document PM6150L compatible
  dt-bindings: leds: pca963x: Convert text bindings to YAML
  leds: an30259a: Use devm_mutex_init() for mutex initialization
  leds: mlxreg: Use devm_mutex_init() for mutex initialization
  leds: nic78bx: Use devm API to cleanup module's resources
  ...
2024-05-22 10:49:54 -07:00
Uros Bizjak
fea0e1820b locking/pvqspinlock: Use try_cmpxchg() in qspinlock_paravirt.h
Use try_cmpxchg(*ptr, &old, new) instead of
cmpxchg(*ptr, old, new) == old in qspinlock_paravirt.h
x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240411192317.25432-2-ubizjak@gmail.com
2024-04-12 11:42:39 +02:00
Uros Bizjak
6a97734f22 locking/pvqspinlock: Use try_cmpxchg_acquire() in trylock_clear_pending()
Replace this pattern in trylock_clear_pending():

    cmpxchg_acquire(*ptr, old, new) == old

... with the simpler and faster:

    try_cmpxchg_acquire(*ptr, &old, new)

The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after the CMPXCHG.

Also change the return type of the function to bool and streamline
the control flow in the _Q_PENDING_BITS == 8 variant a bit.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240325140943.815051-1-ubizjak@gmail.com
2024-04-12 11:40:51 +02:00
George Stark
4cd47222e4 locking/mutex: Introduce devm_mutex_init()
Using of devm API leads to a certain order of releasing resources.
So all dependent resources which are not devm-wrapped should be deleted
with respect to devm-release order. Mutex is one of such objects that
often is bound to other resources and has no own devm wrapping.
Since mutex_destroy() actually does nothing in non-debug builds
frequently calling mutex_destroy() is just ignored which is safe for now
but wrong formally and can lead to a problem if mutex_destroy() will be
extended so introduce devm_mutex_init().

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20240411161032.609544-2-gnstark@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>
2024-04-11 17:34:41 +01:00
Uros Bizjak
79a34e3d84 locking/qspinlock: Use atomic_try_cmpxchg_relaxed() in xchg_tail()
Use atomic_try_cmpxchg_relaxed(*ptr, &old, new) instead of
atomic_cmpxchg_relaxed (*ptr, old, new) == old in xchg_tail().

x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after CMPXCHG.

No functional change intended.

Since this code requires NR_CPUS >= 16k, I have tested it
by unconditionally setting _Q_PENDING_BITS to 1 in
<asm-generic/qspinlock_types.h>.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240321195309.484275-1-ubizjak@gmail.com
2024-04-11 15:14:54 +02:00
Waiman Long
3774b28d8f locking/qspinlock: Always evaluate lockevent* non-event parameter once
The 'inc' parameter of lockevent_add() and the cond parameter of
lockevent_cond_inc() are only evaluated when CONFIG_LOCK_EVENT_COUNTS
is on. That can cause problem if those parameters are expressions
with side effect like a "++". Fix this by evaluating those non-event
parameters once even if CONFIG_LOCK_EVENT_COUNTS is off. This will also
eliminate the need of the __maybe_unused attribute to the wait_early
local variable in pv_wait_node().

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240319005004.1692705-1-longman@redhat.com
2024-03-21 20:45:17 +01:00
Uros Bizjak
ce3576ebd6 locking/rtmutex: Use try_cmpxchg_relaxed() in mark_rt_mutex_waiters()
Use try_cmpxchg() instead of cmpxchg(*ptr, old, new) == old.

The x86 CMPXCHG instruction returns success in the ZF flag, so this change
saves a compare after CMPXCHG (and related move instruction in front of CMPXCHG).

Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when CMPXCHG
fails. There is no need to re-read the value in the loop.

Note that the value from *ptr should be read using READ_ONCE() to prevent
the compiler from merging, refetching or reordering the read.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240124104953.612063-1-ubizjak@gmail.com
2024-03-01 13:02:05 +01:00
Namhyung Kim
f3e3620f1a locking/percpu-rwsem: Trigger contention tracepoints only if contended
We mistakenly always fire lock contention tracepoints in the writer path,
while it should be conditional on the trylock result.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20231108215322.2845536-1-namhyung@kernel.org
2024-02-28 13:10:29 +01:00
Waiman Long
d566c78659 locking/rwsem: Clarify that RWSEM_READER_OWNED is just a hint
Clarify in the comments that the RWSEM_READER_OWNED bit in the owner
field is just a hint, not an authoritative state of the rwsem.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240222150540.79981-4-longman@redhat.com
2024-02-28 13:08:38 +01:00
Waiman Long
ca4bc2e07b locking/qspinlock: Fix 'wait_early' set but not used warning
When CONFIG_LOCK_EVENT_COUNTS is off, the wait_early variable will be
set but not used. This is expected. Recent compilers will not generate
wait_early code in this case.

Add the __maybe_unused attribute to wait_early for suppressing this
W=1 warning.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240222150540.79981-2-longman@redhat.com

Closes: https://lore.kernel.org/oe-kbuild-all/202312260422.f4pK3f9m-lkp@intel.com/
2024-02-28 13:08:37 +01:00
Linus Torvalds
23a80d462c RCU pull request for v6.8
This pull request contains the following branches:
 
 doc.2023.12.13a: Documentation and comment updates.
 
 torture.2023.11.23a: RCU torture, locktorture updates that include
         cleanups; nolibc init build support for mips, ppc and rv64;
         testing of mid stall duration scenario and fixing fqs task
         creation conditions.
 
 fixes.2023.12.13a: Misc fixes, most notably restricting usage of
         RCU CPU stall notifiers, to confine their usage primarily
         to debug kernels.
 
 rcu-tasks.2023.12.12b: RCU tasks minor fixes.
 
 srcu.2023.12.13a: lockdep annotation fix for NMI-safe accesses,
         callback advancing/acceleration cleanup and documentation
         improvements.
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Merge tag 'rcu.release.v6.8' of https://github.com/neeraju/linux

Pull RCU updates from Neeraj Upadhyay:

 - Documentation and comment updates

 - RCU torture, locktorture updates that include cleanups; nolibc init
   build support for mips, ppc and rv64; testing of mid stall duration
   scenario and fixing fqs task creation conditions

 - Misc fixes, most notably restricting usage of RCU CPU stall
   notifiers, to confine their usage primarily to debug kernels

 - RCU tasks minor fixes

 - lockdep annotation fix for NMI-safe accesses, callback
   advancing/acceleration cleanup and documentation improvements

* tag 'rcu.release.v6.8' of https://github.com/neeraju/linux:
  rcu: Force quiescent states only for ongoing grace period
  doc: Clarify historical disclaimers in memory-barriers.txt
  doc: Mention address and data dependencies in rcu_dereference.rst
  doc: Clarify RCU Tasks reader/updater checklist
  rculist.h: docs: Fix wrong function summary
  Documentation: RCU: Remove repeated word in comments
  srcu: Use try-lock lockdep annotation for NMI-safe access.
  srcu: Explain why callbacks invocations can't run concurrently
  srcu: No need to advance/accelerate if no callback enqueued
  srcu: Remove superfluous callbacks advancing from srcu_gp_start()
  rcu: Remove unused macros from rcupdate.h
  rcu: Restrict access to RCU CPU stall notifiers
  rcu-tasks: Mark RCU Tasks accesses to current->rcu_tasks_idle_cpu
  rcutorture: Add fqs_holdoff check before fqs_task is created
  rcutorture: Add mid-sized stall to TREE07
  rcutorture: add nolibc init support for mips, ppc and rv64
  locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains
2024-01-12 16:35:58 -08:00
Linus Torvalds
78273df7f6 header cleanups for 6.8
The goal is to get sched.h down to a type only header, so the main thing
 happening in this patchset is splitting out various _types.h headers and
 dependency fixups, as well as moving some things out of sched.h to
 better locations.
 
 This is prep work for the memory allocation profiling patchset which
 adds new sched.h interdepencencies.
 
 Testing - it's been in -next, and fixes from pretty much all
 architectures have percolated in - nothing major.
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Merge tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs

Pull header cleanups from Kent Overstreet:
 "The goal is to get sched.h down to a type only header, so the main
  thing happening in this patchset is splitting out various _types.h
  headers and dependency fixups, as well as moving some things out of
  sched.h to better locations.

  This is prep work for the memory allocation profiling patchset which
  adds new sched.h interdepencencies"

* tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs: (51 commits)
  Kill sched.h dependency on rcupdate.h
  kill unnecessary thread_info.h include
  Kill unnecessary kernel.h include
  preempt.h: Kill dependency on list.h
  rseq: Split out rseq.h from sched.h
  LoongArch: signal.c: add header file to fix build error
  restart_block: Trim includes
  lockdep: move held_lock to lockdep_types.h
  sem: Split out sem_types.h
  uidgid: Split out uidgid_types.h
  seccomp: Split out seccomp_types.h
  refcount: Split out refcount_types.h
  uapi/linux/resource.h: fix include
  x86/signal: kill dependency on time.h
  syscall_user_dispatch.h: split out *_types.h
  mm_types_task.h: Trim dependencies
  Split out irqflags_types.h
  ipc: Kill bogus dependency on spinlock.h
  shm: Slim down dependencies
  workqueue: Split out workqueue_types.h
  ...
2024-01-10 16:43:55 -08:00
Ingo Molnar
67a1723344 Linux 6.7-rc8
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Merge tag 'v6.7-rc8' into locking/core, to pick up dependent changes

Pick up these commits from Linus's tree:

  b106bcf0f9 ("locking/osq_lock: Clarify osq_wait_next()")
  563adbfc35 ("locking/osq_lock: Clarify osq_wait_next() calling convention")
  7c22309821 ("locking/osq_lock: Move the definition of optimistic_spin_node into osq_lock.c")

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-01-02 10:41:38 +01:00
David Laight
b106bcf0f9 locking/osq_lock: Clarify osq_wait_next()
Directly return NULL or 'next' instead of breaking out of the loop.

Signed-off-by: David Laight <david.laight@aculab.com>
[ Split original patch into two independent parts  - Linus ]
Link: https://lore.kernel.org/lkml/7c8828aec72e42eeb841ca0ee3397e9a@AcuMS.aculab.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-12-30 10:25:51 -08:00
David Laight
563adbfc35 locking/osq_lock: Clarify osq_wait_next() calling convention
osq_wait_next() is passed 'prev' from osq_lock() and NULL from
osq_unlock() but only needs the 'cpu' value to write to lock->tail.

Just pass prev->cpu or OSQ_UNLOCKED_VAL instead.

Should have no effect on the generated code since gcc manages to assume
that 'prev != NULL' due to an earlier dereference.

Signed-off-by: David Laight <david.laight@aculab.com>
[ Changed 'old' to 'old_cpu' by request from Waiman Long  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-12-30 10:25:51 -08:00
David Laight
7c22309821 locking/osq_lock: Move the definition of optimistic_spin_node into osq_lock.c
struct optimistic_spin_node is private to the implementation.
Move it into the C file to ensure nothing is accessing it.

Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-12-30 10:25:51 -08:00
Kent Overstreet
f551103cb9 sched.h: move pid helpers to pid.h
This is needed for killing the sched.h dependency on rcupdate.h, and
pid.h is a better place for this code anyways.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-12-20 19:26:31 -05:00
Jann Horn
a51749ab34 locking/mutex: Document that mutex_unlock() is non-atomic
I have seen several cases of attempts to use mutex_unlock() to release an
object such that the object can then be freed by another task.

This is not safe because mutex_unlock(), in the
MUTEX_FLAG_WAITERS && !MUTEX_FLAG_HANDOFF case, accesses the mutex
structure after having marked it as unlocked; so mutex_unlock() requires
its caller to ensure that the mutex stays alive until mutex_unlock()
returns.

If MUTEX_FLAG_WAITERS is set and there are real waiters, those waiters
have to keep the mutex alive, but we could have a spurious
MUTEX_FLAG_WAITERS left if an interruptible/killable waiter bailed
between the points where __mutex_unlock_slowpath() did the cmpxchg
reading the flags and where it acquired the wait_lock.

( With spinlocks, that kind of code pattern is allowed and, from what I
  remember, used in several places in the kernel. )

Document this, such a semantic difference between mutexes and spinlocks
is fairly unintuitive.

[ mingo: Made the changelog a bit more assertive, refined the comments. ]

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231130204817.2031407-1-jannh@google.com
2023-12-01 11:27:43 +01:00
Peter Zijlstra
bca4104b00 lockdep: Fix block chain corruption
Kent reported an occasional KASAN splat in lockdep. Mark then noted:

> I suspect the dodgy access is to chain_block_buckets[-1], which hits the last 4
> bytes of the redzone and gets (incorrectly/misleadingly) attributed to
> nr_large_chain_blocks.

That would mean @size == 0, at which point size_to_bucket() returns -1
and the above happens.

alloc_chain_hlocks() has 'size - req', for the first with the
precondition 'size >= rq', which allows the 0.

This code is trying to split a block, del_chain_block() takes what we
need, and add_chain_block() puts back the remainder, except in the
above case the remainder is 0 sized and things go sideways.

Fixes: 810507fe6f ("locking/lockdep: Reuse freed chain_hlocks entries")
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lkml.kernel.org/r/20231121114126.GH8262@noisy.programming.kicks-ass.net
2023-11-24 11:04:54 +01:00
Paul E. McKenney
69dcbbd804 locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains
One letter difference is really not enough, so this commit changes
call_rcu_chain to call_rcu_chain_list.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
2023-11-23 11:58:18 +05:30
Linus Torvalds
2656821f1f RCU pull request for v6.7
This pull request contains the following branches:
 
 rcu/torture: RCU torture, locktorture and generic torture infrastructure
 	updates that include various fixes, cleanups and consolidations.
 	Among the user visible things, ftrace dumps can now be found into
 	their own file, and module parameters get better documented and
 	reported on dumps.
 
 rcu/fixes: Generic and misc fixes all over the place. Some highlights:
 
 	* Hotplug handling has seen some light cleanups and comments.
 
 	* An RCU barrier can now be triggered through sysfs to serialize
 	memory stress testing and avoid OOM.
 
 	* Object information is now dumped in case of invalid callback
 	invocation.
 
 	* Also various SRCU issues, too hard to trigger to deserve urgent
 	pull requests, have been fixed.
 
 rcu/docs: RCU documentation updates
 
 rcu/refscale: RCU reference scalability test minor fixes and doc
 	improvements.
 
 rcu/tasks: RCU tasks minor fixes
 
 rcu/stall: Stall detection updates. Introduce RCU CPU Stall notifiers
 	that allows a subsystem to provide informations to help debugging.
 	Also cure some false positive stalls.
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Merge tag 'rcu-next-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks

Pull RCU updates from Frederic Weisbecker:

 - RCU torture, locktorture and generic torture infrastructure updates
   that include various fixes, cleanups and consolidations.

   Among the user visible things, ftrace dumps can now be found into
   their own file, and module parameters get better documented and
   reported on dumps.

 - Generic and misc fixes all over the place. Some highlights:

     * Hotplug handling has seen some light cleanups and comments

     * An RCU barrier can now be triggered through sysfs to serialize
       memory stress testing and avoid OOM

     * Object information is now dumped in case of invalid callback
       invocation

     * Also various SRCU issues, too hard to trigger to deserve urgent
       pull requests, have been fixed

 - RCU documentation updates

 - RCU reference scalability test minor fixes and doc improvements.

 - RCU tasks minor fixes

 - Stall detection updates. Introduce RCU CPU Stall notifiers that
   allows a subsystem to provide informations to help debugging. Also
   cure some false positive stalls.

* tag 'rcu-next-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (56 commits)
  srcu: Only accelerate on enqueue time
  locktorture: Check the correct variable for allocation failure
  srcu: Fix callbacks acceleration mishandling
  rcu: Comment why callbacks migration can't wait for CPUHP_RCUTREE_PREP
  rcu: Standardize explicit CPU-hotplug calls
  rcu: Conditionally build CPU-hotplug teardown callbacks
  rcu: Remove references to rcu_migrate_callbacks() from diagrams
  rcu: Assume rcu_report_dead() is always called locally
  rcu: Assume IRQS disabled from rcu_report_dead()
  rcu: Use rcu_segcblist_segempty() instead of open coding it
  rcu: kmemleak: Ignore kmemleak false positives when RCU-freeing objects
  srcu: Fix srcu_struct node grpmask overflow on 64-bit systems
  torture: Convert parse-console.sh to mktemp
  rcutorture: Traverse possible cpu to set maxcpu in rcu_nocb_toggle()
  rcutorture: Replace schedule_timeout*() 1-jiffy waits with HZ/20
  torture: Add kvm.sh --debug-info argument
  locktorture: Rename readers_bind/writers_bind to bind_readers/bind_writers
  doc: Catch-up update for locktorture module parameters
  locktorture: Add call_rcu_chains module parameter
  locktorture: Add new module parameters to lock_torture_print_module_parms()
  ...
2023-10-30 18:01:41 -10:00
Linus Torvalds
3cf3fabccb Locking changes in this cycle are:
- Futex improvements:
 
     - Add the 'futex2' syscall ABI, which is an attempt to get away from the
       multiplex syscall and adds a little room for extentions, while lifting
       some limitations.
 
     - Fix futex PI recursive rt_mutex waiter state bug
 
     - Fix inter-process shared futexes on no-MMU systems
 
     - Use folios instead of pages
 
  - Micro-optimizations of locking primitives:
 
     - Improve arch_spin_value_unlocked() on asm-generic ticket spinlock
       architectures, to improve lockref code generation.
 
     - Improve the x86-32 lockref_get_not_zero() main loop by adding
       build-time CMPXCHG8B support detection for the relevant lockref code,
       and by better interfacing the CMPXCHG8B assembly code with the compiler.
 
     - Introduce arch_sync_try_cmpxchg() on x86 to improve sync_try_cmpxchg()
       code generation. Convert some sync_cmpxchg() users to sync_try_cmpxchg().
 
     - Micro-optimize rcuref_put_slowpath()
 
  - Locking debuggability improvements:
 
     - Improve CONFIG_DEBUG_RT_MUTEXES=y to have a fast-path as well
 
     - Enforce atomicity of sched_submit_work(), which is de-facto atomic but
       was un-enforced previously.
 
     - Extend <linux/cleanup.h>'s no_free_ptr() with __must_check semantics
 
     - Fix ww_mutex self-tests
 
     - Clean up const-propagation in <linux/seqlock.h> and simplify
       the API-instantiation macros a bit.
 
  - RT locking improvements:
 
     - Provide the rt_mutex_*_schedule() primitives/helpers and use them
       in the rtmutex code to avoid recursion vs. rtlock on the PI state.
 
     - Add nested blocking lockdep asserts to rt_mutex_lock(), rtlock_lock()
       and rwbase_read_lock().
 
  - Plus misc fixes & cleanups
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Info Molnar:
 "Futex improvements:

   - Add the 'futex2' syscall ABI, which is an attempt to get away from
     the multiplex syscall and adds a little room for extentions, while
     lifting some limitations.

   - Fix futex PI recursive rt_mutex waiter state bug

   - Fix inter-process shared futexes on no-MMU systems

   - Use folios instead of pages

  Micro-optimizations of locking primitives:

   - Improve arch_spin_value_unlocked() on asm-generic ticket spinlock
     architectures, to improve lockref code generation

   - Improve the x86-32 lockref_get_not_zero() main loop by adding
     build-time CMPXCHG8B support detection for the relevant lockref
     code, and by better interfacing the CMPXCHG8B assembly code with
     the compiler

   - Introduce arch_sync_try_cmpxchg() on x86 to improve
     sync_try_cmpxchg() code generation. Convert some sync_cmpxchg()
     users to sync_try_cmpxchg().

   - Micro-optimize rcuref_put_slowpath()

  Locking debuggability improvements:

   - Improve CONFIG_DEBUG_RT_MUTEXES=y to have a fast-path as well

   - Enforce atomicity of sched_submit_work(), which is de-facto atomic
     but was un-enforced previously.

   - Extend <linux/cleanup.h>'s no_free_ptr() with __must_check
     semantics

   - Fix ww_mutex self-tests

   - Clean up const-propagation in <linux/seqlock.h> and simplify the
     API-instantiation macros a bit

  RT locking improvements:

   - Provide the rt_mutex_*_schedule() primitives/helpers and use them
     in the rtmutex code to avoid recursion vs. rtlock on the PI state.

   - Add nested blocking lockdep asserts to rt_mutex_lock(),
     rtlock_lock() and rwbase_read_lock()

  .. plus misc fixes & cleanups"

* tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  futex: Don't include process MM in futex key on no-MMU
  locking/seqlock: Fix grammar in comment
  alpha: Fix up new futex syscall numbers
  locking/seqlock: Propagate 'const' pointers within read-only methods, remove forced type casts
  locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
  locking/seqlock: Change __seqprop() to return the function pointer
  locking/seqlock: Simplify SEQCOUNT_LOCKNAME()
  locking/atomics: Use atomic_try_cmpxchg_release() to micro-optimize rcuref_put_slowpath()
  locking/atomic, xen: Use sync_try_cmpxchg() instead of sync_cmpxchg()
  locking/atomic/x86: Introduce arch_sync_try_cmpxchg()
  locking/atomic: Add generic support for sync_try_cmpxchg() and its fallback
  locking/seqlock: Fix typo in comment
  futex/requeue: Remove unnecessary ‘NULL’ initialization from futex_proxy_trylock_atomic()
  locking/local, arch: Rewrite local_add_unless() as a static inline function
  locking/debug: Fix debugfs API return value checks to use IS_ERR()
  locking/ww_mutex/test: Make sure we bail out instead of livelock
  locking/ww_mutex/test: Fix potential workqueue corruption
  locking/ww_mutex/test: Use prng instead of rng to avoid hangs at bootup
  futex: Add sys_futex_requeue()
  futex: Add flags2 argument to futex_requeue()
  ...
2023-10-30 12:38:48 -10:00
Brian Foster
957e48087d locking: export contention tracepoints for bcachefs six locks
The bcachefs implementation of six locks is intended to land in
generic locking code in the long term, but has been pulled into the
bcachefs subsystem for internal use for the time being. This code
lift breaks the bcachefs module build as six locks depend a couple
of the generic locking tracepoints. Export these tracepoint symbols
for bcachefs.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-19 14:47:33 -04:00
Lucy Mielke
ac8b60be07 locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
On an allyesconfig, with "treat warnings as errors" unset, GCC emits
these warnings:

	kernel/locking/lockdep_proc.c:438:32: Warning: Format specifier '%lld' may
		be truncated when writing 1 to 17 bytes into a region
		of size 15 [-Wformat-truncation=]

	kernel/locking/lockdep_proc.c:438:31: Note: Format directive argument is
		in the range [-9223372036854775, 9223372036854775]

	kernel/locking/lockdep_proc.c:438:9: Note: 'snprintf' has output
		between 5 and 22 bytes into a target of size 15

In seq_time(), the longest s64 is "-9223372036854775808"-ish, which
converted to the fixed-point float format is "-9223372036854775.80": 21 bytes,
plus termination is another byte: 22. Therefore, a larger buffer size
of 22 is needed here - not 15. The code was safe due to the snprintf().

Fix it.

Signed-off-by: Lucy Mielke <lucymielke@icloud.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/ZSfOEHRkZAWaQr3U@fedora.fritz.box
2023-10-12 20:37:59 +02:00
Dan Carpenter
cefe8ce559 locktorture: Check the correct variable for allocation failure
There is a typo so this checks the wrong variable.  "chains" plural vs
"chain" singular.  We already know that "chains" is non-zero.

Fixes: 7f993623e9 ("locktorture: Add call_rcu_chains module parameter")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-10-11 15:55:26 +02:00
Atul Kumar Pant
8788c6c2fe locking/debug: Fix debugfs API return value checks to use IS_ERR()
Update the checking of return values from debugfs_create_file()
and debugfs_create_dir() to use IS_ERR().

Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20230807121834.7438-1-atulpant.linux@gmail.com
2023-10-03 10:11:25 +02:00
Paul E. McKenney
2273799c29 locktorture: Rename readers_bind/writers_bind to bind_readers/bind_writers
This commit renames the readers_bind and writers_bind module parameters
to bind_readers and bind_writers, respectively.  This provides added
clarity via the imperative mode and better organizes the documentation.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:02 +02:00
Paul E. McKenney
7f993623e9 locktorture: Add call_rcu_chains module parameter
When running locktorture on large systems, there will normally be
enough RCU activity to ensure that there is a grace period in flight
at all times.  However, on smaller systems, RCU might well be idle the
majority of the time.  This situation can be inconvenient in cases where
the RCU CPU stall warning is part of the debugging process.

This commit therefore adds an call_rcu_chains module parameter to
locktorture, allowing the user to specify the desired number of
self-propagating call_rcu() chains.  For good measure, immediately
before invoking call_rcu(), the self-propagating RCU callback invokes
start_poll_synchronize_rcu() to force the immediate start of a grace
period, with the call_rcu() forcing another to start shortly thereafter.

Booting with locktorture.call_rcu_chains=2 increases the probability
of a stuck locking primitive resulting in an RCU CPU stall warning from
about 25% to nearly 100%.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:02 +02:00
Paul E. McKenney
00c24c9cfa locktorture: Add new module parameters to lock_torture_print_module_parms()
This commit adds new module parameters to lock_torture_print_module_parms,
and alphabetizes things while in the area.  This change makes locktorture
test results more useful and self-contained.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:02 +02:00
Paul E. McKenney
e3bdaefbcc locktorture: Add acq_writer_lim to complain about long acquistion times
This commit adds a locktorture.acq_writer_lim module parameter that
specifies the maximum number of jiffies that is expected to be consumed
by write-side lock acquisition.  If this limit is exceeded, a WARN_ONCE()
causes a splat.  Note that this limit applies to the main lock acquisition
only, not to any nested acquisitions.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:01 +02:00
Paul E. McKenney
84cee9e72e locktorture: Consolidate "if" statements in lock_torture_writer()
There is a pair of adjacent "if" statements with identical conditions in
the lock_torture_writer() function.  This commit therefore combines them.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:01 +02:00
Paul E. McKenney
31742a56c6 locktorture: Alphabetize torture_param() entries
There are getting to be too many module parameters for a random list to be
comfortable, so this commit alphabetizes the list.  Strictly code motion.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:01 +02:00
Paul E. McKenney
73e3412424 locktorture: Add readers_bind and writers_bind module parameters
This commit adds readers_bind and writers_bind module parameters to
locktorture in order to skew tests across socket boundaries.  This skewing
is intended to provide additional variable-latency stress on the primitive
under test.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2023-09-24 17:24:01 +02:00
John Stultz
cfa92b6d52 locking/ww_mutex/test: Make sure we bail out instead of livelock
I've seen what appears to be livelocks in the stress_inorder_work()
function, and looking at the code it is clear we can have a case
where we continually retry acquiring the locks and never check to
see if we have passed the specified timeout.

This patch reworks that function so we always check the timeout
before iterating through the loop again.

I believe others may have hit this previously here:

  https://lore.kernel.org/lkml/895ef450-4fb3-5d29-a6ad-790657106a5a@intel.com/

Reported-by: Li Zhijian <zhijianx.li@intel.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-4-jstultz@google.com
2023-09-22 09:43:41 +02:00
John Stultz
bccdd80890 locking/ww_mutex/test: Fix potential workqueue corruption
In some cases running with the test-ww_mutex code, I was seeing
odd behavior where sometimes it seemed flush_workqueue was
returning before all the work threads were finished.

Often this would cause strange crashes as the mutexes would be
freed while they were being used.

Looking at the code, there is a lifetime problem as the
controlling thread that spawns the work allocates the
"struct stress" structures that are passed to the workqueue
threads. Then when the workqueue threads are finished,
they free the stress struct that was passed to them.

Unfortunately the workqueue work_struct node is in the stress
struct. Which means the work_struct is freed before the work
thread returns and while flush_workqueue is waiting.

It seems like a better idea to have the controlling thread
both allocate and free the stress structures, so that we can
be sure we don't corrupt the workqueue by freeing the structure
prematurely.

So this patch reworks the test to do so, and with this change
I no longer see the early flush_workqueue returns.

Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-3-jstultz@google.com
2023-09-22 09:43:40 +02:00
John Stultz
4812c54dc0 locking/ww_mutex/test: Use prng instead of rng to avoid hangs at bootup
Booting w/ qemu without kvm, and with 64 cpus, I noticed we'd
sometimes hung task watchdog splats in get_random_u32_below()
when using the test-ww_mutex stress test.

While entropy exhaustion is no longer an issue, the RNG may be
slower early in boot. The test-ww_mutex code will spawn off
128 threads (2x cpus) and each thread will call
get_random_u32_below() a number of times to generate a random
order of the 16 locks.

This intense use takes time and without kvm, qemu can be slow
enough that we trip the hung task watchdogs.

For this test, we don't need true randomness, just mixed up
orders for testing ww_mutex lock acquisitions, so it changes
the logic to use the prng instead, which takes less time
and avoids the watchdgos.

Feedback would be appreciated!

Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-2-jstultz@google.com
2023-09-22 09:43:40 +02:00
Thomas Gleixner
45f67f30a2 locking/rtmutex: Add a lockdep assert to catch potential nested blocking
There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition
functions, but that vanished in one of the rtmutex overhauls.

Bring it back in form of a lockdep assert to catch code paths which take
rtmutex based locks with current::pi_blocked_on != NULL.

Reported-by: Crystal Wood <swood@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@linutronix.de
2023-09-20 09:31:14 +02:00
Sebastian Andrzej Siewior
d14f9e930b locking/rtmutex: Use rt_mutex specific scheduler helpers
Have rt_mutex use the rt_mutex specific scheduler helpers to avoid
recursion vs rtlock on the PI state.

[[ peterz: adapted to new names ]]

Reported-by: Crystal Wood <swood@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-6-bigeasy@linutronix.de
2023-09-20 09:31:13 +02:00
Sebastian Andrzej Siewior
af9f006393 locking/rtmutex: Avoid unconditional slowpath for DEBUG_RT_MUTEXES
With DEBUG_RT_MUTEXES enabled the fast-path rt_mutex_cmpxchg_acquire()
always fails and all lock operations take the slow path.

Provide a new helper inline rt_mutex_try_acquire() which maps to
rt_mutex_cmpxchg_acquire() in the non-debug case. For the debug case
it invokes rt_mutex_slowtrylock() which can acquire a non-contended
rtmutex under full debug coverage.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-3-bigeasy@linutronix.de
2023-09-20 09:31:11 +02:00
Linus Torvalds
d68b4b6f30 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
("refactor Kconfig to consolidate KEXEC and CRASH options").
 
 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h").
 
 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands").
 
 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions").
 
 - Switch the handling of kdump from a udev scheme to in-kernel handling,
   by Eric DeVolder ("crash: Kernel handling of CPU and memory hot
   un/plug").
 
 - Many singleton patches to various parts of the tree
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Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...
2023-08-29 14:53:51 -07:00
Linus Torvalds
97efd28334 Misc x86 cleanups.
The following commit deserves special mention:
 
    22dc02f81c Revert "sched/fair: Move unused stub functions to header"
 
 This is in x86/cleanups, because the revert is a re-application of a
 number of cleanups that got removed inadvertedly.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 cleanups from Ingo Molnar:
 "The following commit deserves special mention:

   22dc02f81c Revert "sched/fair: Move unused stub functions to header"

  This is in x86/cleanups, because the revert is a re-application of a
  number of cleanups that got removed inadvertedly"

[ This also effectively undoes the amd_check_microcode() microcode
  declaration change I had done in my microcode loader merge in commit
  42a7f6e3ff ("Merge tag 'x86_microcode_for_v6.6_rc1' [...]").

  I picked the declaration change by Arnd from this branch instead,
  which put it in <asm/processor.h> instead of <asm/microcode.h> like I
  had done in my merge resolution   - Linus ]

* tag 'x86-cleanups-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/uv: Refactor code using deprecated strncpy() interface to use strscpy()
  x86/hpet: Refactor code using deprecated strncpy() interface to use strscpy()
  x86/platform/uv: Refactor code using deprecated strcpy()/strncpy() interfaces to use strscpy()
  x86/qspinlock-paravirt: Fix missing-prototype warning
  x86/paravirt: Silence unused native_pv_lock_init() function warning
  x86/alternative: Add a __alt_reloc_selftest() prototype
  x86/purgatory: Include header for warn() declaration
  x86/asm: Avoid unneeded __div64_32 function definition
  Revert "sched/fair: Move unused stub functions to header"
  x86/apic: Hide unused safe_smp_processor_id() on 32-bit UP
  x86/cpu: Fix amd_check_microcode() declaration
2023-08-28 17:05:58 -07:00
Linus Torvalds
68cadad11f RCU pull request for v6.6
doc.2023.07.14b: Documentation updates.
 
 fixes.2023.08.16a: Miscellaneous fixes, perhaps most notably simplifying
 	SRCU_NOTIFIER_INIT() as suggested.
 
 rcu-tasks.2023.07.24a:  RCU Tasks updates, most notably treating
 	Tasks RCU callbacks as lazy while still treating synchronous
 	grace periods as urgent.  Also fixes one bug that restores the
 	ability to apply debug-objects to RCU Tasks and another that
 	fixes a race condition that could result in false-positive
 	failures of the boot-time self-test code.
 
 rcuscale.2023.07.14b: RCU-scalability performance-test updates,
 	most notably adding the ability to measure the RCU-Tasks's
 	grace-period kthread's CPU consumption.  This proved
 	quite useful for the rcu-tasks.2023.07.24a work.
 
 refscale.2023.07.14b: Reference-acquisition/release performance-test
 	updates, including a fix for an uninitialized wait_queue_head_t.
 
 torture.2023.08.14a: Miscellaneous torture-test updates.
 
 torturescripts.2023.07.20a: Torture-test scripting updates, including
 	removal of the non-longer-functional formal-verification scripts,
 	test builds of individual RCU Tasks flavors, better diagnostics
 	for loss of connectivity for distributed rcutorture tests,
 	disabling of reboot loops in qemu/KVM-based rcutorture testing,
 	and passing of init parameters to rcutorture's init program.
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Merge tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

 - Documentation updates

 - Miscellaneous fixes, perhaps most notably simplifying
   SRCU_NOTIFIER_INIT() as suggested

 - RCU Tasks updates, most notably treating Tasks RCU callbacks as lazy
   while still treating synchronous grace periods as urgent. Also fixes
   one bug that restores the ability to apply debug-objects to RCU Tasks
   and another that fixes a race condition that could result in
   false-positive failures of the boot-time self-test code

 - RCU-scalability performance-test updates, most notably adding the
   ability to measure the RCU-Tasks's grace-period kthread's CPU
   consumption. This proved quite useful for the RCU Tasks work

 - Reference-acquisition/release performance-test updates, including a
   fix for an uninitialized wait_queue_head_t

 - Miscellaneous torture-test updates

 - Torture-test scripting updates, including removal of the
   non-longer-functional formal-verification scripts, test builds of
   individual RCU Tasks flavors, better diagnostics for loss of
   connectivity for distributed rcutorture tests, disabling of reboot
   loops in qemu/KVM-based rcutorture testing, and passing of init
   parameters to rcutorture's init program

* tag 'rcu.2023.08.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (64 commits)
  rcu: Use WRITE_ONCE() for assignments to ->next for rculist_nulls
  rcu: Make the rcu_nocb_poll boot parameter usable via boot config
  rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load
  srcu,notifier: Remove #ifdefs in favor of SRCU Tiny srcu_usage
  rcutorture: Stop right-shifting torture_random() return values
  torture: Stop right-shifting torture_random() return values
  torture: Move stutter_wait() timeouts to hrtimers
  torture: Move torture_shuffle() timeouts to hrtimers
  torture: Move torture_onoff() timeouts to hrtimers
  torture: Make torture_hrtimeout_*() use TASK_IDLE
  torture: Add lock_torture writer_fifo module parameter
  torture: Add a kthread-creation callback to _torture_create_kthread()
  rcu-tasks: Fix boot-time RCU tasks debug-only deadlock
  rcu-tasks: Permit use of debug-objects with RCU Tasks flavors
  checkpatch: Complain about unexpected uses of RCU Tasks Trace
  torture: Cause mkinitrd.sh to indicate failure on compile errors
  torture: Make init program dump command-line arguments
  torture: Switch qemu from -nographic to -display none
  torture: Add init-program support for loongarch
  torture: Avoid torture-test reboot loops
  ...
2023-08-28 13:19:28 -07:00
Helge Deller
0a6b58c5cd lockdep: fix static memory detection even more
On the parisc architecture, lockdep reports for all static objects which
are in the __initdata section (e.g. "setup_done" in devtmpfs,
"kthreadd_done" in init/main.c) this warning:

	INFO: trying to register non-static key.

The warning itself is wrong, because those objects are in the __initdata
section, but the section itself is on parisc outside of range from
_stext to _end, which is why the static_obj() functions returns a wrong
answer.

While fixing this issue, I noticed that the whole existing check can
be simplified a lot.
Instead of checking against the _stext and _end symbols (which include
code areas too) just check for the .data and .bss segments (since we check a
data object). This can be done with the existing is_kernel_core_data()
macro.

In addition objects in the __initdata section can be checked with
init_section_contains(), and is_kernel_rodata() allows keys to be in the
_ro_after_init section.

This partly reverts and simplifies commit bac59d18c7 ("x86/setup: Fix static
memory detection").

Link: https://lkml.kernel.org/r/ZNqrLRaOi/3wPAdp@p100
Fixes: bac59d18c7 ("x86/setup: Fix static memory detection")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21 13:46:24 -07:00
Dietmar Eggemann
5d248bb39f torture: Add lock_torture writer_fifo module parameter
This commit adds a module parameter that causes the locktorture writer
to run at real-time priority.

To use it:
insmod /lib/modules/torture.ko random_shuffle=1
insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1
													^^^^^^^^^^^^^

A predecessor to this patch has been helpful to uncover issues with the
proxy-execution series.

[ paulmck: Remove locktorture-specific code from kernel/torture.c. ]

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: kernel-team@android.com
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2023-08-14 15:01:07 -07:00
Arnd Bergmann
8874a414f8 x86/qspinlock-paravirt: Fix missing-prototype warning
__pv_queued_spin_unlock_slowpath() is defined in a header file as
a global function, and designed to be called from inline asm, but
there is no prototype visible in the definition:

  kernel/locking/qspinlock_paravirt.h:493:1: error: no previous \
    prototype for '__pv_queued_spin_unlock_slowpath' [-Werror=missing-prototypes]

Add this to the x86 header that contains the inline asm calling it,
and ensure this gets included before the definition, rather than
after it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230803082619.1369127-8-arnd@kernel.org
2023-08-03 17:15:05 +02:00
Peter Zijlstra
f7853c3424 locking/rtmutex: Fix task->pi_waiters integrity
Henry reported that rt_mutex_adjust_prio_check() has an ordering
problem and puts the lie to the comment in [7]. Sharing the sort key
between lock->waiters and owner->pi_waiters *does* create problems,
since unlike what the comment claims, holding [L] is insufficient.

Notably, consider:

	A
      /   \
     M1   M2
     |     |
     B     C

That is, task A owns both M1 and M2, B and C block on them. In this
case a concurrent chain walk (B & C) will modify their resp. sort keys
in [7] while holding M1->wait_lock and M2->wait_lock. So holding [L]
is meaningless, they're different Ls.

This then gives rise to a race condition between [7] and [11], where
the requeue of pi_waiters will observe an inconsistent tree order.

	B				C

  (holds M1->wait_lock,		(holds M2->wait_lock,
   holds B->pi_lock)		 holds A->pi_lock)

  [7]
  waiter_update_prio();
  ...
  [8]
  raw_spin_unlock(B->pi_lock);
  ...
  [10]
  raw_spin_lock(A->pi_lock);

				[11]
				rt_mutex_enqueue_pi();
				// observes inconsistent A->pi_waiters
				// tree order

Fixing this means either extending the range of the owner lock from
[10-13] to [6-13], with the immediate problem that this means [6-8]
hold both blocked and owner locks, or duplicating the sort key.

Since the locking in chain walk is horrible enough without having to
consider pi_lock nesting rules, duplicate the sort key instead.

By giving each tree their own sort key, the above race becomes
harmless, if C sees B at the old location, then B will correct things
(if they need correcting) when it walks up the chain and reaches A.

Fixes: fb00aca474 ("rtmutex: Turn the plist into an rb-tree")
Reported-by: Henry Wu <triangletrap12@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Henry Wu <triangletrap12@gmail.com>
Link: https://lkml.kernel.org/r/20230707161052.GF2883469%40hirez.programming.kicks-ass.net
2023-07-17 13:59:10 +02:00
Linus Torvalds
77b1a7f7a0 - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in
top-level directories.
 
 - Douglas Anderson has added a new "buddy" mode to the hardlockup
   detector.  It permits the detector to work on architectures which
   cannot provide the required interrupts, by having CPUs periodically
   perform checks on other CPUs.
 
 - Zhen Lei has enhanced kexec's ability to support two crash regions.
 
 - Petr Mladek has done a lot of cleanup on the hard lockup detector's
   Kconfig entries.
 
 - And the usual bunch of singleton patches in various places.
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Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-mm updates from Andrew Morton:

 - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level
   directories

 - Douglas Anderson has added a new "buddy" mode to the hardlockup
   detector. It permits the detector to work on architectures which
   cannot provide the required interrupts, by having CPUs periodically
   perform checks on other CPUs

 - Zhen Lei has enhanced kexec's ability to support two crash regions

 - Petr Mladek has done a lot of cleanup on the hard lockup detector's
   Kconfig entries

 - And the usual bunch of singleton patches in various places

* tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  kernel/time/posix-stubs.c: remove duplicated include
  ocfs2: remove redundant assignment to variable bit_off
  watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY
  powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h
  devres: show which resource was invalid in __devm_ioremap_resource()
  watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH
  watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64
  watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific
  watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h
  watchdog/hardlockup: make the config checks more straightforward
  watchdog/hardlockup: sort hardlockup detector related config values a logical way
  watchdog/hardlockup: move SMP barriers from common code to buddy code
  watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY
  watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
  watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called
  watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog()
  watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy()
  watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick()
  watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe()
  watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails
  ...
2023-06-28 10:59:38 -07:00
Linus Torvalds
bc6cb4d5bc Locking changes for v6.5:
- Introduce cmpxchg128() -- aka. the demise of cmpxchg_double().
 
   The cmpxchg128() family of functions is basically & functionally
   the same as cmpxchg_double(), but with a saner interface: instead
   of a 6-parameter horror that forced u128 - u64/u64-halves layout
   details on the interface and exposed users to complexity,
   fragility & bugs, use a natural 3-parameter interface with u128 types.
 
 - Restructure the generated atomic headers, and add
   kerneldoc comments for all of the generic atomic{,64,_long}_t
   operations. Generated definitions are much cleaner now,
   and come with documentation.
 
 - Implement lock_set_cmp_fn() on lockdep, for defining an ordering
   when taking multiple locks of the same type. This gets rid of
   one use of lockdep_set_novalidate_class() in the bcache code.
 
 - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended
   variable shadowing generating garbage code on Clang on certain
   ARM builds.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:

 - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double()

   The cmpxchg128() family of functions is basically & functionally the
   same as cmpxchg_double(), but with a saner interface.

   Instead of a 6-parameter horror that forced u128 - u64/u64-halves
   layout details on the interface and exposed users to complexity,
   fragility & bugs, use a natural 3-parameter interface with u128
   types.

 - Restructure the generated atomic headers, and add kerneldoc comments
   for all of the generic atomic{,64,_long}_t operations.

   The generated definitions are much cleaner now, and come with
   documentation.

 - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when
   taking multiple locks of the same type.

   This gets rid of one use of lockdep_set_novalidate_class() in the
   bcache code.

 - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable
   shadowing generating garbage code on Clang on certain ARM builds.

* tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc
  percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg()
  locking/atomic: treewide: delete arch_atomic_*() kerneldoc
  locking/atomic: docs: Add atomic operations to the driver basic API documentation
  locking/atomic: scripts: generate kerneldoc comments
  docs: scripts: kernel-doc: accept bitwise negation like ~@var
  locking/atomic: scripts: simplify raw_atomic*() definitions
  locking/atomic: scripts: simplify raw_atomic_long*() definitions
  locking/atomic: scripts: split pfx/name/sfx/order
  locking/atomic: scripts: restructure fallback ifdeffery
  locking/atomic: scripts: build raw_atomic_long*() directly
  locking/atomic: treewide: use raw_atomic*_<op>()
  locking/atomic: scripts: add trivial raw_atomic*_<op>()
  locking/atomic: scripts: factor out order template generation
  locking/atomic: scripts: remove leftover "${mult}"
  locking/atomic: scripts: remove bogus order parameter
  locking/atomic: xtensa: add preprocessor symbols
  locking/atomic: x86: add preprocessor symbols
  locking/atomic: sparc: add preprocessor symbols
  locking/atomic: sh: add preprocessor symbols
  ...
2023-06-27 14:14:30 -07:00
Linus Torvalds
af96134dc8 RCU pull request for v6.5
This pull contains the following branches:
 
 doc.2023.05.10a: Documentation updates
 
 fixes.2023.05.11a: Miscellaneous fixes, perhaps most notably:
 
 o	Remove RCU_NONIDLE().  The new visibility of most of the idle
 	loop to RCU has obsoleted this API.
 
 o	Make the RCU_SOFTIRQ callback-invocation time limit also apply
 	to the rcuc kthreads that invoke callbacks for CONFIG_PREEMPT_RT.
 
 o	Add a jiffies-based callback-invocation time limit to handle
 	long-running callbacks.  (The local_clock() function is only
 	invoked once per 32 callbacks due to its high overhead.)
 
 o	Stop rcu_tasks_invoke_cbs() from using never-onlined CPUs,
 	which fixes a bug that can occur on systems with non-contiguous
 	CPU numbering.
 
 kvfree.2023.05.10a: kvfree_rcu updates
 
 o	Eliminate the single-argument variant of k[v]free_rcu() now
 	that all uses have been converted to k[v]free_rcu_mightsleep().
 
 o	Add WARN_ON_ONCE() checks for k[v]free_rcu*() freeing callbacks
 	too soon.  Yes, this is closing the barn door after the horse
 	has escaped, but Murphy says that there will be more horses.
 
 nocb.2023.05.11a: Callback-offloading updates
 
 o	Fix a number of bugs involving the shrinker and lazy callbacks.
 
 rcu-tasks.2023.05.10a: Tasks RCU updates
 
 torture.2023.05.15a: Torture-test updates
 
 rcu-urgent.2023.06.06a: Urgent SRCU fix (already pulled)
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Merge tag 'rcu.2023.06.22a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:
 "Documentation updates

  Miscellaneous fixes, perhaps most notably:

   - Remove RCU_NONIDLE(). The new visibility of most of the idle loop
     to RCU has obsoleted this API.

   - Make the RCU_SOFTIRQ callback-invocation time limit also apply to
     the rcuc kthreads that invoke callbacks for CONFIG_PREEMPT_RT.

   - Add a jiffies-based callback-invocation time limit to handle
     long-running callbacks. (The local_clock() function is only invoked
     once per 32 callbacks due to its high overhead.)

   - Stop rcu_tasks_invoke_cbs() from using never-onlined CPUs, which
     fixes a bug that can occur on systems with non-contiguous CPU
     numbering.

  kvfree_rcu updates:

   - Eliminate the single-argument variant of k[v]free_rcu() now that
     all uses have been converted to k[v]free_rcu_mightsleep().

   - Add WARN_ON_ONCE() checks for k[v]free_rcu*() freeing callbacks too
     soon. Yes, this is closing the barn door after the horse has
     escaped, but Murphy says that there will be more horses.

  Callback-offloading updates:

   - Fix a number of bugs involving the shrinker and lazy callbacks.

  Tasks RCU updates

  Torture-test updates"

* tag 'rcu.2023.06.22a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (32 commits)
  torture: Remove duplicated argument -enable-kvm for ppc64
  doc/rcutorture: Add description of rcutorture.stall_cpu_block
  rcu/rcuscale: Stop kfree_scale_thread thread(s) after unloading rcuscale
  rcu/rcuscale: Move rcu_scale_*() after kfree_scale_cleanup()
  rcutorture: Correct name of use_softirq module parameter
  locktorture: Add long_hold to adjust lock-hold delays
  rcu/nocb: Make shrinker iterate only over NOCB CPUs
  rcu-tasks: Stop rcu_tasks_invoke_cbs() from using never-onlined CPUs
  rcu: Make rcu_cpu_starting() rely on interrupts being disabled
  rcu: Mark rcu_cpu_kthread() accesses to ->rcu_cpu_has_work
  rcu: Mark additional concurrent load from ->cpu_no_qs.b.exp
  rcu: Employ jiffies-based backstop to callback time limit
  rcu: Check callback-invocation time limit for rcuc kthreads
  rcu: Remove RCU_NONIDLE()
  rcu: Add more RCU files to kernel-api.rst
  rcu-tasks: Clarify the cblist_init_generic() function's pr_info() output
  rcu-tasks: Avoid pr_info() with spin lock in cblist_init_generic()
  rcu/nocb: Recheck lazy callbacks under the ->nocb_lock from shrinker
  rcu/nocb: Fix shrinker race against callback enqueuer
  rcu/nocb: Protect lazy shrinker against concurrent (de-)offloading
  ...
2023-06-27 10:37:01 -07:00
Arnd Bergmann
ff7138813a locking: add lockevent_read() prototype
lockevent_read() has a __weak definition and the only caller in
kernel/locking/lock_events.c, plus a strong definition in qspinlock_stat.h
that overrides it, but no other declaration.  This causes a W=1 warning:

kernel/locking/lock_events.c:61:16: error: no previous prototype for 'lockevent_read' [-Werror=missing-prototypes]

Add shared prototype to avoid the warnings.

Link: https://lkml.kernel.org/r/20230517131102.934196-7-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-09 17:44:15 -07:00