diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 12879f6c1ec3..a273183c37a0 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -636,9 +636,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 			 * all over without going into schedule to try
 			 * to get the lock now:
 			 */
-			if (unlikely(!waiter.task))
+			if (unlikely(!waiter.task)) {
+				/*
+				 * Reset the return value. We might
+				 * have returned with -EDEADLK and the
+				 * owner released the lock while we
+				 * were walking the pi chain.
+				 */
+				ret = 0;
 				continue;
-
+			}
 			if (unlikely(ret))
 				break;
 		}