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sched/membarrier: Fix private expedited registration check

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[ Upstream commit fc0d77387cb5ae883fd774fc559e056a8dde024c ]

Fix a logic flaw in the way membarrier_register_private_expedited()
handles ready state checks for private expedited sync core and private
expedited registrations.

If a private expedited membarrier registration is first performed, and
then a private expedited sync_core registration is performed, the ready
state check will skip the second registration when it really should not.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-2-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Mathieu Desnoyers 2019-09-19 13:36:59 -04:00 committed by Greg Kroah-Hartman
parent e250f2b6aa
commit 6cb7aa1b4f
1 changed files with 1 additions and 1 deletions
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2
kernel/sched/membarrier.c
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@ -235,7 +235,7 @@ static int membarrier_register_private_expedited(int flags)
* groups, which use the same mm. (CLONE_VM but not
* CLONE_THREAD).
*/
if (atomic_read(&mm->membarrier_state) & state)
if ((atomic_read(&mm->membarrier_state) & state) == state)
return 0;
atomic_or(MEMBARRIER_STATE_PRIVATE_EXPEDITED, &mm->membarrier_state);
if (flags & MEMBARRIER_FLAG_SYNC_CORE)