Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932322Ab2JDHsx (ORCPT ); Thu, 4 Oct 2012 03:48:53 -0400 Received: from TYO200.gate.nec.co.jp ([210.143.35.50]:36143 "EHLO tyo200.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754441Ab2JDHsv (ORCPT ); Thu, 4 Oct 2012 03:48:51 -0400 X-Greylist: delayed 362 seconds by postgrey-1.27 at vger.kernel.org; Thu, 04 Oct 2012 03:48:50 EDT Date: Thu, 4 Oct 2012 16:37:16 +0900 From: Daisuke Nishimura To: LKML , cgroups Cc: Ben Blum , Tejun Heo , Li Zefan , Daisuke Nishimura Subject: [REGRESSION] cgroup: notify_on_release may not be triggered in some cases Message-Id: <20121004163716.64dae034dab9eafa2b6e6a8f@mxp.nes.nec.co.jp> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 3.2.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1763 Lines: 57 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 Cc: Tejun Heo Cc: Li Zefan Cc: # v3.0.x and later Signed-off-by: Daisuke Nishimura --- This patch is based on v3.6. kernel/cgroup.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 7981850..7d01182 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1923,9 +1923,8 @@ 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); } /** -- 1.7.1 -- 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/