diff --git a/[refs] b/[refs]
index 39e397e6a9a1..fc954a7f8aea 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8a35241803eeb0e9fd3fe27835d6b2775c73b641
+refs/heads/master: eac1b5e57d7abc836e78fd3fbcf77dbeed01edc9
diff --git a/trunk/fs/exec.c b/trunk/fs/exec.c
index b08367abf30e..d219541db06c 100644
--- a/trunk/fs/exec.c
+++ b/trunk/fs/exec.c
@@ -967,6 +967,14 @@ static int de_thread(struct task_struct *tsk)
 
 		BUG_ON(leader->exit_state != EXIT_ZOMBIE);
 		leader->exit_state = EXIT_DEAD;
+
+		/*
+		 * We are going to release_task()->ptrace_unlink() silently,
+		 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
+		 * the tracer wont't block again waiting for this thread.
+		 */
+		if (unlikely(leader->ptrace))
+			__wake_up_parent(leader, leader->parent);
 		write_unlock_irq(&tasklist_lock);
 
 		release_task(leader);