]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
pids: introduce change_pid() helper
authorOleg Nesterov <oleg@tv-sign.ru>
Wed, 30 Apr 2008 07:54:26 +0000 (00:54 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 30 Apr 2008 15:29:48 +0000 (08:29 -0700)
commit24336eaeecea860b2a82530e07c80bc7e0558b73
tree12a34660f732e12ba18262083c1a2eea5a824f6a
parent65450cebc6a2efde80ed45514f727e6e4dc1eafd
pids: introduce change_pid() helper

Based on Eric W. Biederman's idea.

Without tasklist_lock held task_session()/task_pgrp() can return NULL if the
caller races with setprgp()/setsid() which does detach_pid() + attach_pid().
This can happen even if task == current.

Intoduce the new helper, change_pid(), which should be used instead.  This way
the caller always sees the special pid != NULL, either old or new.

Also change the prototype of attach_pid(), it always returns 0 and nobody
check the returned value.

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>
include/linux/pid.h
kernel/pid.c