From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933795Ab2KZRhD (ORCPT ); Mon, 26 Nov 2012 12:37:03 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47917 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933681Ab2KZRLq (ORCPT ); Mon, 26 Nov 2012 12:11:46 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Ben Blum , Daisuke Nishimura , Tejun Heo , Herton Ronaldo Krzesinski Subject: [PATCH 189/270] cgroup: notify_on_release may not be triggered in some cases Date: Mon, 26 Nov 2012 14:57:59 -0200 Message-Id: <1353949160-26803-190-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> References: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7u1 -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. Cc: Ben Blum Acked-by: Li Zefan Signed-off-by: Daisuke Nishimura Signed-off-by: Tejun Heo Signed-off-by: Herton Ronaldo Krzesinski --- kernel/cgroup.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 15462a0..63c9596 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1927,9 +1927,8 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp, * 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); } /** -- 1.7.9.5