Messages in this thread Patch in this message | | | Subject | Re: [tip:locking/core] rtmutex: Deboost before waking up the top waiter | From | Mike Galbraith <> | Date | Wed, 05 Apr 2017 10:08:27 +0200 |
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locking/rtmutex: Fix preempt leak in __rt_mutex_futex_unlock()
mark_wakeup_next_waiter() already disables preemption, doing so again leaves us with an unpaired preempt_disable().
Signed-off-by: Mike Galbraith <efault@gmx.de> --- kernel/locking/rtmutex.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1581,13 +1581,13 @@ bool __sched __rt_mutex_futex_unlock(str return false; /* done */ } - mark_wakeup_next_waiter(wake_q, lock); /* - * We've already deboosted, retain preempt_disabled when dropping - * the wait_lock to avoid inversion until the wakeup. Matched - * by rt_mutex_postunlock(); + * We've already deboosted, mark_wakeup_next_waiter() will + * retain preempt_disabled when we drop the wait_lock, to + * avoid inversion prior to the wakeup. preempt_disable() + * therein pairs with rt_mutex_postunlock(). */ - preempt_disable(); + mark_wakeup_next_waiter(wake_q, lock); return true; /* call postunlock() */ }
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