Peter Zijlstra 23a67ddd46 locking/mcs: Fix mcs_spin_lock() ordering ... commit 920c720aa5 upstream. Similar to commit b4b29f9485 ("locking/osq: Fix ordering of node initialisation in osq_lock") the use of xchg_acquire() is fundamentally broken with MCS like constructs. Furthermore, it turns out we rely on the global transitivity of this operation because the unlock path observes the pointer with a READ_ONCE(), not an smp_load_acquire(). This is non-critical because the MCS code isn't actually used and mostly serves as documentation, a stepping stone to the more complex things we've build on top of the idea. Reported-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Fixes: 3552a07a9c ("locking/mcs: Use acquire/release semantics") Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-05-04 14:48:50 -07:00
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lglock.c
lockdep.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
locktorture.c
Makefile
mcs_spinlock.h	locking/mcs: Fix mcs_spin_lock() ordering	2016-05-04 14:48:50 -07:00
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
osq_lock.c
percpu-rwsem.c
qrwlock.c
qspinlock.c
qspinlock_paravirt.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem-spinlock.c
rwsem-xadd.c
rwsem.c
rwsem.h
semaphore.c
spinlock.c
spinlock_debug.c