Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755138Ab2JZAPV (ORCPT ); Thu, 25 Oct 2012 20:15:21 -0400 Received: from mail.kernel.org ([198.145.19.201]:53964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754591Ab2JZAIW (ORCPT ); Thu, 25 Oct 2012 20:08:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Li Zefan , Ben Blum , Daisuke Nishimura , Tejun Heo Subject: [ 50/85] cgroup: notify_on_release may not be triggered in some cases Date: Thu, 25 Oct 2012 17:06:08 -0700 Message-Id: <20121026000036.149998987@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.2.421.g261b511 In-Reply-To: <20121026000031.107227138@linuxfoundation.org> References: <20121026000031.107227138@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1853 Lines: 61 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daisuke Nishimura commit 1f5320d5972aa50d3e8d2b227b636b370e608359 upstream. notify_on_release must be triggered when the last process in a cgroup is move to another. But if the first(and only) process in a cgroup is moved to another, notify_on_release is not triggered. # mkdir /cgroup/cpu/SRC # mkdir /cgroup/cpu/DST # # echo 1 >/cgroup/cpu/SRC/notify_on_release # echo 1 >/cgroup/cpu/DST/notify_on_release # # sleep 300 & [1] 8629 # # echo 8629 >/cgroup/cpu/SRC/tasks # echo 8629 >/cgroup/cpu/DST/tasks -> notify_on_release for /SRC must be triggered at this point, but it isn't. This is because put_css_set() is called before setting CGRP_RELEASABLE in cgroup_task_migrate(), and is a regression introduce by the commit:74a1166d(cgroups: make procs file writable), which was merged into v3.0. Acked-by: Li Zefan Cc: Ben Blum Signed-off-by: Daisuke Nishimura Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- kernel/cgroup.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1923,9 +1923,8 @@ static void cgroup_task_migrate(struct c * trading it for newcg is protected by cgroup_mutex, we're safe to drop * it here; it will be freed under RCU. */ - put_css_set(oldcg); - set_bit(CGRP_RELEASABLE, &oldcgrp->flags); + put_css_set(oldcg); } /** -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/