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.desnoy...@efficios.com>
Cc: "Paul E. McKenney" <paul...@linux.ibm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Russell King - ARM Linux admin <li...@armlinux.org.uk>
Cc: Chris Metcalf <cmetc...@ezchip.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: Kirill Tkhai <tk...@yandex.ru>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
---
kernel/sched/membarrier.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index aa8d75804108..5110d91b1b0e 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -226,7 +226,7 @@ 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)
--
2.17.1
