[PATCH] workqueue: Fix possible unexpectedly worker wakeup before started

[Lai Jiangshan]

If a worker is wokenup unexpectedly, it will start to work incorretly.
Although it hardly happen, we should catch it and wait for being started
if it does happen.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
---
 kernel/workqueue.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 82ef9f3..bee5fe1 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2284,6 +2284,12 @@ static int worker_thread(void *__worker)
 	struct worker *worker = __worker;
 	struct worker_pool *pool = worker->pool;
 
+	if (WARN_ON_ONCE(!(worker->flags & WORKER_STARTED))) {
+		/* The worker is wokenup unexpectedly before started */
+		mutex_lock(&pool->manager_mutex);
+		mutex_unlock(&pool->manager_mutex);
+	}
+
 	/* tell the scheduler that this is a workqueue worker */
 	worker->task->flags |= PF_WQ_WORKER;
 woke_up:
-- 
1.7.4.4

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