From 5ecfbae093f0c37311e89b29bfc0c9d586eace87 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 15 Feb 2006 22:50:10 +0300
Subject: [PATCH] fix zap_thread's ptrace related problems

1. The tracee can go from ptrace_stop() to do_signal_stop()
   after __ptrace_unlink(p).

2. It is unsafe to __ptrace_unlink(p) while p->parent may wait
   for tasklist_lock in ptrace_detach().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 fs/exec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs')

diff --git a/fs/exec.c b/fs/exec.c
index 055378d..0e1c950 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1403,7 +1403,7 @@ static void zap_threads (struct mm_struct *mm)
 		do_each_thread(g,p) {
 			if (mm == p->mm && p != tsk &&
 			    p->ptrace && p->parent->mm == mm) {
-				__ptrace_unlink(p);
+				__ptrace_detach(p, 0);
 			}
 		} while_each_thread(g,p);
 		write_unlock_irq(&tasklist_lock);
-- 
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