diff --git a/fs/signalfd.c b/fs/signalfd.c
index 79c1eea..7ae2a57 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -33,7 +33,11 @@
 void signalfd_cleanup(struct sighand_struct *sighand)
 {
 	wait_queue_head_t *wqh = &sighand->signalfd_wqh;
-
+	/*
+	 * The lockless check can race with remove_wait_queue() in progress,
+	 * but in this case its caller should run under rcu_read_lock() and
+	 * sighand_cachep is SLAB_DESTROY_BY_RCU, we can safely return.
+	 */
 	if (likely(!waitqueue_active(wqh)))
 		return;