--- linux/kernel/signal.c.orig	
+++ linux/kernel/signal.c	
@@ -1386,12 +1386,12 @@ static inline void __wake_up_parent(stru
 	 * Fortunately this is not necessary for thread groups:
 	 */
 	if (p->tgid == tsk->tgid) {
-		wake_up_interruptible(&tsk->wait_chldexit);
+		wake_up_interruptible_sync(&tsk->wait_chldexit);
 		return;
 	}
 
 	do {
-		wake_up_interruptible(&tsk->wait_chldexit);
+		wake_up_interruptible_sync(&tsk->wait_chldexit);
 		tsk = next_thread(tsk);
 		if (tsk->signal != parent->signal)
 			BUG();