Index: generic/src/synch/waitq.c
===================================================================
--- generic/src/synch/waitq.c	(revision 9c1c677109242df29e86affb8527c36e254031e2)
+++ generic/src/synch/waitq.c	(revision bffa0b06adea1b03489a7f0c461606f20a0da9b2)
@@ -148,4 +148,7 @@
 			goto grab_locks;	/* avoid deadlock */
 		}
+
+		if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))
+			t->timeout_pending = false;
 
 		list_remove(&t->wq_link);