| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Thu, 7 Sep 2017 12:38:47 +0200 |
| Subject: locking/rtmutex: don't drop the wait_lock twice |
| |
| Since the futex rework, __rt_mutex_start_proxy_lock() does no longer |
| acquire the wait_lock so it must not drop it. Otherwise the lock is not |
| only unlocked twice but also the preemption counter is underflown. |
| |
| It is okay to remove that line because this function does not disable |
| interrupts nor does it acquire the ->wait_lock. The caller does this so it is |
| wrong do it here (after the futex rework). |
| |
| Cc: rt-stable@vger.kernel.org #v4.9.18-rt14+ |
| Reported-by: Gusenleitner Klaus <gus@keba.com> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| kernel/locking/rtmutex.c | 1 - |
| 1 file changed, 1 deletion(-) |
| |
| --- a/kernel/locking/rtmutex.c |
| +++ b/kernel/locking/rtmutex.c |
| @@ -1745,7 +1745,6 @@ int __rt_mutex_start_proxy_lock(struct r |
| raw_spin_lock(&task->pi_lock); |
| if (task->pi_blocked_on) { |
| raw_spin_unlock(&task->pi_lock); |
| - raw_spin_unlock_irq(&lock->wait_lock); |
| return -EAGAIN; |
| } |
| task->pi_blocked_on = PI_REQUEUE_INPROGRESS; |
