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linux/kernel/locking
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Peter Zijlstra eeb6b4a096 lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop 
[ Upstream commit 99143f82a2 ]

While reviewing another read_slowpath patch, both Will and I noticed
another missing ACQUIRE, namely:

  X = 0;

  CPU0			CPU1

  rwsem_down_read()
    for (;;) {
      set_current_state(TASK_UNINTERRUPTIBLE);

                        X = 1;
                        rwsem_up_write();
                          rwsem_mark_wake()
                            atomic_long_add(adjustment, &sem->count);
                            smp_store_release(&waiter->task, NULL);

      if (!waiter.task)
        break;

      ...
    }

  r = X;

Allows 'r == 0'.

Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-06 10:23:28 +02:00
..
lock_events_list.h
locking/rwsem: Enable lock event counting
2019-04-10 10:56:06 +02:00
lock_events.c
locking/lock_events: Don't show pvqspinlock events on bare metal
2019-04-10 10:56:05 +02:00
lock_events.h
locking/lock_events: Use this_cpu_add() when necessary
2019-05-24 14:17:18 -07:00
lockdep_internals.h
locking/lockdep: Test all incompatible scenarios at once in check_irq_usage()
2019-04-29 08:29:20 +02:00
lockdep_proc.c
locking/lockdep: Hide unused 'class' variable
2019-07-31 07:24:55 +02:00
lockdep_states.h
locking/lockdep: Rework FS_RECLAIM annotation
2017-08-10 12:29:03 +02:00
lockdep.c
locking/lockdep: Fix merging of hlocks with non-zero references
2019-07-26 09:10:20 +02:00
locktorture.c
locktorture: NULL cxt.lwsa and cxt.lrsa to allow bad-arg detection
2019-03-26 14:42:53 -07:00
Makefile
locking/lock_events: Make lock_events available for all archs & other locks
2019-04-10 10:56:04 +02:00
mcs_spinlock.h
locking/mcs: Use smp_cond_load_acquire() in MCS spin loop
2018-04-27 09:48:49 +02:00
mutex-debug.c
locking/mutex: Replace spin_is_locked() with lockdep
2018-11-12 09:06:22 -08:00
mutex-debug.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
mutex.c
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
mutex.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
osq_lock.c
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
percpu-rwsem.c
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
qrwlock.c
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
qspinlock_paravirt.h
locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs
2019-04-10 10:56:03 +02:00
qspinlock_stat.h
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
qspinlock.c
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
rtmutex_common.h
locking/rtmutex: Handle non enqueued waiters gracefully in remove_waiter()
2018-03-28 23:01:30 +02:00
rtmutex-debug.c
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
rtmutex-debug.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
rtmutex.c
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
rtmutex.h
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 11:10:55 +01:00
rwsem-xadd.c
lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop
2019-09-06 10:23:28 +02:00
rwsem.c
locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro
2019-04-10 10:56:03 +02:00
rwsem.h
locking/rwsem: Prevent unneeded warning during locking selftest
2019-04-14 11:09:35 +02:00
semaphore.c
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436
2019-06-05 17:37:17 +02:00
spinlock_debug.c
mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors
2019-04-08 11:59:47 +01:00
spinlock.c
asm-generic/mmiowb: Add generic implementation of mmiowb() tracking
2019-04-08 11:59:39 +01:00
test-ww_mutex.c
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9
2019-05-21 11:28:40 +02:00