Index: generic/src/synch/waitq.c
===================================================================
--- generic/src/synch/waitq.c	(revision 9c1c677109242df29e86affb8527c36e254031e2)
+++ generic/src/synch/waitq.c	(revision 0dbc4e7a921e1e08e6a60698a953242fa5a643b3)
@@ -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);