[PATCH] worker_thread race fix

Fix a waitqueue-handling race in worker_thread().

kernel/workqueue.c

@@ -201,19 +201,20 @@ static int worker_thread(void *__cwq)
 	siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD));
 	do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
 
+	set_current_state(TASK_INTERRUPTIBLE);
 	while (!kthread_should_stop()) {
-		set_task_state(current, TASK_INTERRUPTIBLE);
-
 		add_wait_queue(&cwq->more_work, &wait);
 		if (list_empty(&cwq->worklist))
 			schedule();
 		else
-			set_task_state(current, TASK_RUNNING);
+			__set_current_state(TASK_RUNNING);
 		remove_wait_queue(&cwq->more_work, &wait);
 
 		if (!list_empty(&cwq->worklist))
 			run_workqueue(cwq);
+		set_current_state(TASK_INTERRUPTIBLE);
 	}
+	__set_current_state(TASK_RUNNING);
 	return 0;
 }