From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbYKSIbR (ORCPT ); Wed, 19 Nov 2008 03:31:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752007AbYKSIbB (ORCPT ); Wed, 19 Nov 2008 03:31:01 -0500 Received: from e28smtp03.in.ibm.com ([59.145.155.3]:51326 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752166AbYKSIbA (ORCPT ); Wed, 19 Nov 2008 03:31:00 -0500 Message-ID: <4923CEBF.8000402@linux.vnet.ibm.com> Date: Wed, 19 Nov 2008 14:00:55 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 2.0.0.17 (X11/20080925) MIME-Version: 1.0 To: Andrew Morton CC: Li Zefan , Paul Menage , LKML , Linux Containers , stable@kernel.org Subject: Re: [PATCH] cgroups: fix a serious bug in cgroupstats References: <4923CAF1.1020404@cn.fujitsu.com> <20081119002552.3840e3d2.akpm@linux-foundation.org> In-Reply-To: <20081119002552.3840e3d2.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Wed, 19 Nov 2008 16:14:41 +0800 Li Zefan wrote: > >> Try this, and you'll get oops immediately: > > I guess that's wrong. > >> # cd Documentation/accounting/ >> # gcc -o getdelays getdelays.c >> # mount -t cgroup -o debug xxx /mnt >> # ./getdelays -C /mnt/tasks >> >> Because a normal file's dentry->d_fsdata is a pointer to struct cftype, >> not struct cgroup. >> >> After the patch, it returns EINVAL if we try to get cgroupstats >> from a normal file. >> >> CC: Balbir Singh >> Signed-off-by: Li Zefan >> --- >> kernel/cgroup.c | 7 +++++-- >> 1 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/cgroup.c b/kernel/cgroup.c >> index 358e775..f6f5219 100644 >> --- a/kernel/cgroup.c >> +++ b/kernel/cgroup.c >> @@ -2039,10 +2039,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) >> struct cgroup *cgrp; >> struct cgroup_iter it; >> struct task_struct *tsk; >> + >> /* >> - * Validate dentry by checking the superblock operations >> + * Validate dentry by checking the superblock operations, >> + * and make sure it's a directory. >> */ >> - if (dentry->d_sb->s_op != &cgroup_ops) >> + if (dentry->d_sb->s_op != &cgroup_ops || >> + !S_ISDIR(dentry->d_inode->i_mode)) >> goto err; >> >> ret = 0; > > The patch applies OK to 2.6.25, 2.6.26 and to 2.6.27. I marked it as > needing backport to those kernel versions. Please let me know if that > was inappropriate. > Thanks, it does need to be backported. Thanks Li for spotting the problem. -- Balbir