android_kernel_motorola_sm6375/kernel/locking
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Marco Elver c120c3dbeb locking/spinlock/debug: Fix various data races
[ Upstream commit 1a365e822372ba24c9da0822bc583894f6f3d821 ]

This fixes various data races in spinlock_debug. By testing with KCSAN,
it is observable that the console gets spammed with data races reports,
suggesting these are extremely frequent.

Example data race report:

  read to 0xffff8ab24f403c48 of 4 bytes by task 221 on cpu 2:
   debug_spin_lock_before kernel/locking/spinlock_debug.c:85 [inline]
   do_raw_spin_lock+0x9b/0x210 kernel/locking/spinlock_debug.c:112
   __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
   _raw_spin_lock+0x39/0x40 kernel/locking/spinlock.c:151
   spin_lock include/linux/spinlock.h:338 [inline]
   get_partial_node.isra.0.part.0+0x32/0x2f0 mm/slub.c:1873
   get_partial_node mm/slub.c:1870 [inline]
  <snip>

  write to 0xffff8ab24f403c48 of 4 bytes by task 167 on cpu 3:
   debug_spin_unlock kernel/locking/spinlock_debug.c:103 [inline]
   do_raw_spin_unlock+0xc9/0x1a0 kernel/locking/spinlock_debug.c:138
   __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:159 [inline]
   _raw_spin_unlock_irqrestore+0x2d/0x50 kernel/locking/spinlock.c:191
   spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
   free_debug_processing+0x1b3/0x210 mm/slub.c:1214
   __slab_free+0x292/0x400 mm/slub.c:2864
  <snip>

As a side-effect, with KCSAN, this eventually locks up the console, most
likely due to deadlock, e.g. .. -> printk lock -> spinlock_debug ->
KCSAN detects data race -> kcsan_print_report() -> printk lock ->
deadlock.

This fix will 1) avoid the data races, and 2) allow using lock debugging
together with KCSAN.

Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Marco Elver <elver@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/r/20191120155715.28089-1-elver@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-12 12:21:13 +01:00
..
lock_events.c
lock_events.h locking/lock_events: Use raw_cpu_{add,inc}() for stats 2019-06-03 12:32:56 +02:00
lock_events_list.h locking/rwsem: Adaptive disabling of reader optimistic spinning 2019-06-17 12:28:09 +02:00
lockdep.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-16 16:49:55 -07:00
lockdep_internals.h locking/lockdep: Report more stack trace statistics 2019-07-25 15:43:28 +02:00
lockdep_proc.c locking/lockdep: Report more stack trace statistics 2019-07-25 15:43:28 +02:00
lockdep_states.h
locktorture.c
Makefile locking/rwsem: Merge rwsem.h and rwsem-xadd.c into rwsem.c 2019-06-17 12:27:57 +02:00
mcs_spinlock.h
mutex-debug.c
mutex-debug.h
mutex.c mutex: Fix up mutex_waiter usage 2019-08-08 09:09:25 +02:00
mutex.h mutex: Fix up mutex_waiter usage 2019-08-08 09:09:25 +02:00
osq_lock.c
percpu-rwsem.c Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2019-06-28 19:46:47 +02:00
qrwlock.c
qspinlock.c
qspinlock_paravirt.h Revert "locking/pvqspinlock: Don't wait if vCPU is preempted" 2019-09-25 10:22:37 +02:00
qspinlock_stat.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex.c sched/core: Convert get_task_struct() to return the task 2019-07-25 15:51:54 +02:00
rtmutex.h
rtmutex_common.h
rwsem.c locking/rwsem: Check for operations on an uninitialized rwsem 2019-08-06 12:49:15 +02:00
rwsem.h locking/rwsem: Merge rwsem.h and rwsem-xadd.c into rwsem.c 2019-06-17 12:27:57 +02:00
semaphore.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436 2019-06-05 17:37:17 +02:00
spinlock.c
spinlock_debug.c locking/spinlock/debug: Fix various data races 2020-01-12 12:21:13 +01:00
test-ww_mutex.c