locking/mutex: Explicitly mark task as running after wakeup

By the time we wake up and get the lock after being asleep
in the slowpath, we better be running. As good practice,
be explicit about this and avoid any mischief.
Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1421717961.4903.11.camel@stgolabs.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

kernel/locking/mutex.c

@@ -587,6 +587,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		schedule_preempt_disabled();
 		spin_lock_mutex(&lock->wait_lock, flags);
 	}
+	__set_task_state(task, TASK_RUNNING);
+
 	mutex_remove_waiter(lock, &waiter, current_thread_info());
 	/* set it to 0 if there are no waiters left: */
 	if (likely(list_empty(&lock->wait_list)))