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>
diff --git a/kernel/sys.c b/kernel/sys.c
index 47c30a20..5d0b44c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -978,8 +978,7 @@
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));
}