From 88b964548d4f808a609c41baf868a7f2e6ab3635 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Thu, 21 Jul 2011 20:00:43 +0200
Subject: [PATCH] --- yaml --- r: 256869 b: refs/heads/master c:
 eac1b5e57d7abc836e78fd3fbcf77dbeed01edc9 h: refs/heads/master i:   256867:
 3a8e29bb6af895b764013a68ecac3457adf4e123 v: v3

---
 [refs]          | 2 +-
 trunk/fs/exec.c | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

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);