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 <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Russell King - ARM Linux admin <[email protected]> Cc: Chris Metcalf <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Kirill Tkhai <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> --- 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 d564ca1b5d69..e962d47ea6b4 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -265,7 +265,7 @@ 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) & ready_state)) + if ((atomic_read(&mm->membarrier_state) & ready_state) == ready_state) return 0; if (flags & MEMBARRIER_FLAG_SYNC_CORE) set_state |= MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE; -- 2.17.1
