Manfred Spraul 30e5bc30f5 ipc/sem.c: update/correct memory barriers ... commit 3ed1f8a99d70ea1cd1508910eb107d0edcae5009 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2015-09-13 09:07:59 -07:00
..
compat.c	ipc: fix compat msgrcv with negative msgtyp	2015-04-19 10:10:50 +02:00
compat_mq.c
ipc_sysctl.c	ipc: always handle a new value of auto_msgmni	2014-11-21 09:22:54 -08:00
ipcns_notifier.c
Makefile
mq_sysctl.c	ipc,mqueue: remove limits for the amount of system-wide queues	2014-03-06 21:30:12 -08:00
mqueue.c	ipc: modify message queue accounting to not take kernel data structures into account	2015-08-16 20:51:40 -07:00
msg.c	ipc: Fix 2 bugs in msgrcv() MSG_COPY implementation	2014-03-23 21:38:17 -07:00
msgutil.c	ipc, msg: fix message length check for negative values	2013-12-04 10:56:10 -08:00
namespace.c	ipc: drop ipc_lock_by_ptr	2013-10-18 07:45:48 -07:00
sem.c	ipc/sem.c: update/correct memory barriers	2015-09-13 09:07:59 -07:00
shm.c	ipc,shm: fix shm_file deletion races	2013-11-29 11:11:41 -08:00
syscall.c	get rid of union semop in sys_semctl(2) arguments	2013-03-05 15:14:16 -05:00
util.c	ipc: update locking scheme comments	2013-12-04 10:56:12 -08:00
util.h	ipc, msg: fix message length check for negative values	2013-12-04 10:56:10 -08:00