https://github.com/torvalds/linux
Revision 3ed1f8a99d70ea1cd1508910eb107d0edcae5009 authored by Manfred Spraul on 14 August 2015, 22:35:10 UTC, committed by Linus Torvalds on 14 August 2015, 22:56:32 UTC
sem_lock() did not properly pair memory barriers: !spin_is_locked() and spin_unlock_wait() are both only control barriers. The code needs an acquire barrier, otherwise the cpu might perform read operations before the lock test. As no primitive exists inside <include/spinlock.h> and since it seems noone wants another primitive, the code creates a local primitive within ipc/sem.c. With regards to -stable: The change of sem_wait_array() is a bugfix, the change to sem_lock() is a nop (just a preprocessor redefinition to improve the readability). The bugfix is necessary for all kernels that use sem_wait_array() (i.e.: starting from 3.10). Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Reported-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: <stable@vger.kernel.org> [3.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 3ed1f8a99d70ea1cd1508910eb107d0edcae5009 authored by Manfred Spraul on 14 August 2015, 22:35:10 UTC
ipc/sem.c: update/correct memory barriers
ipc/sem.c: update/correct memory barriers
Tip revision: 3ed1f8a
File | Mode | Size |
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mpu401 | ||
opl3 | ||
opl4 | ||
pcsp | ||
vx | ||
Kconfig | -rw-r--r-- | 6.8 KB |
Makefile | -rw-r--r-- | 788 bytes |
aloop.c | -rw-r--r-- | 35.4 KB |
dummy.c | -rw-r--r-- | 32.0 KB |
ml403-ac97cr.c | -rw-r--r-- | 39.6 KB |
mtpav.c | -rw-r--r-- | 19.8 KB |
mts64.c | -rw-r--r-- | 26.3 KB |
pcm-indirect2.c | -rw-r--r-- | 16.8 KB |
pcm-indirect2.h | -rw-r--r-- | 5.1 KB |
portman2x4.c | -rw-r--r-- | 25.2 KB |
serial-u16550.c | -rw-r--r-- | 30.7 KB |
virmidi.c | -rw-r--r-- | 5.5 KB |
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