diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 828e582..4fcb75b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -427,6 +427,8 @@
  * flush_work - block until a work_struct's callback has terminated
  * @work: the work which is to be flushed
  *
+ * Returns false if @work has already terminated.
+ *
  * It is expected that, prior to calling flush_work(), the caller has
  * arranged for the work to not be requeued, otherwise it doesn't make
  * sense to use this function.
@@ -442,6 +444,9 @@
 	if (!cwq)
 		return 0;
 
+	lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+	lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+
 	prev = NULL;
 	spin_lock_irq(&cwq->lock);
 	if (!list_empty(&work->entry)) {