Will Deacon 3b3fdf10a8 locking/pvqspinlock: Order pv_unhash() after cmpxchg() on unlock slowpath ... When we unlock in __pv_queued_spin_unlock(), a failed cmpxchg() on the lock value indicates that we need to take the slow-path and unhash the corresponding node blocked on the lock. Since a failed cmpxchg() does not provide any memory-ordering guarantees, it is possible that the node data could be read before the cmpxchg() on weakly-ordered architectures and therefore return a stale value, leading to hash corruption and/or a BUG(). This patch adds an smb_rmb() following the failed cmpxchg operation, so that the unhashing is ordered after the lock has been checked. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com> [ Added more comments] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <Waiman.Long@hp.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Steve Capper <Steve.Capper@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150713155830.GL2632@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2015-08-03 10:57:09 +02:00
..
lglock.c	sched/stop_machine: Fix deadlock between multiple stop_two_cpus()	2015-06-19 10:03:12 +02:00
lockdep.c	Merge branch 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-06-24 15:09:40 -07:00
lockdep_internals.h
lockdep_proc.c	lockdep: Fix a race between /proc/lock_stat and module unload	2015-06-07 15:46:30 +02:00
lockdep_states.h
locktorture.c	locktorture: Change longdelay_us to longdelay_ms	2015-05-27 12:59:57 -07:00
Makefile	rtmutex: Delete scriptable tester	2015-07-20 11:45:45 +02:00
mcs_spinlock.h
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
osq_lock.c
percpu-rwsem.c
qrwlock.c	locking/qrwlock: Better optimization for interrupt context readers	2015-07-06 14:11:28 +02:00
qspinlock.c	locking/pvqspinlock: Implement simple paravirt support for the qspinlock	2015-05-08 12:37:05 +02:00
qspinlock_paravirt.h	locking/pvqspinlock: Order pv_unhash() after cmpxchg() on unlock slowpath	2015-08-03 10:57:09 +02:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex.c	rtmutex: Delete scriptable tester	2015-07-20 11:45:45 +02:00
rtmutex.h
rtmutex_common.h	rtmutex: Delete scriptable tester	2015-07-20 11:45:45 +02:00
rwsem-spinlock.c
rwsem-xadd.c
rwsem.c
rwsem.h
semaphore.c
spinlock.c
spinlock_debug.c