From 83beaf3c6c75b36b7c9be7f555c8cf7797842cc5 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 30 Apr 2008 00:54:27 -0700
Subject: [PATCH] pids: sys_setpgid: use change_pid() helper

Use change_pid() instead of detach_pid() + attach_pid() in sys_setpgid().

This way task_pgrp() is not NULL in between.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc:  "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/sys.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index 47c30a20b55..5d0b44cd435 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -978,8 +978,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 		goto out;
 
 	if (task_pgrp(p) != pgrp) {
-		detach_pid(p, PIDTYPE_PGID);
-		attach_pid(p, PIDTYPE_PGID, pgrp);
+		change_pid(p, PIDTYPE_PGID, pgrp);
 		set_task_pgrp(p, pid_nr(pgrp));
 	}