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99143f82a2
linux-next/kernel/locking
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Peter Zijlstra 99143f82a2 lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop 
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>
2019-07-25 15:39:24 +02:00
..
lock_events_list.h locking/rwsem: Adaptive disabling of reader optimistic spinning 2019-06-17 12:28:09 +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 raw_cpu_{add,inc}() for stats 2019-06-03 12:32:56 +02:00
lockdep_internals.h locking/lockdep: increase size of counters for lockdep statistics 2019-06-25 10:17:08 +02:00
lockdep_proc.c locking/lockdep: Fix lock used or unused stats error 2019-07-13 11:24:53 +02:00
lockdep_states.h locking/lockdep: Rework FS_RECLAIM annotation 2017-08-10 12:29:03 +02:00
lockdep.c locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING 2019-06-25 10:17:07 +02:00
locktorture.c torture: Allow inter-stutter interval to be specified 2019-05-28 09:06:09 -07:00
Makefile locking/rwsem: Merge rwsem.h and rwsem-xadd.c into rwsem.c 2019-06-17 12:27:57 +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 docs: locking: convert docs to ReST and rename to *.rst 2019-07-15 08:53:27 -03:00
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 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 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 docs: locking: convert docs to ReST and rename to *.rst 2019-07-15 08:53:27 -03:00
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.c lcoking/rwsem: Add missing ACQUIRE to read_slowpath sleep loop 2019-07-25 15:39:24 +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_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