Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756259AbaDQFx5 (ORCPT ); Thu, 17 Apr 2014 01:53:57 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:37334 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751418AbaDQFx4 (ORCPT ); Thu, 17 Apr 2014 01:53:56 -0400 Message-ID: <534F6C44.2060800@huawei.com> Date: Thu, 17 Apr 2014 13:53:08 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Tejun Heo CC: LKML , Cgroups Subject: [PATCH] cgroup: fix the retry path of cgroup_mount() Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we hit the retry path, we'll call parse_cgroupfs_options() again, but the string we pass to it has been modified by the previous call to this function. This bug can be observed by: # mount -t cgroup -o name=foo,cpuset xxx /mnt && umount /mnt && \ mount -t cgroup -o name=foo,cpuset xxx /mnt mount: wrong fs type, bad option, bad superblock on xxx, missing codepage or helper program, or other error ... The second mount passed "name=foo,cpuset" to the parser, and then it hit the retry path and call the parser again, but this time the string passed to the parser is "name=foo". To fix this, we avoid calling parse_cgroupfs_options() again in this case. Signed-off-by: Li Zefan --- kernel/cgroup.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 08c4439..9d6be07 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1580,7 +1580,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, */ if (!use_task_css_set_links) cgroup_enable_task_cg_lists(); -retry: + mutex_lock(&cgroup_tree_mutex); mutex_lock(&cgroup_mutex); @@ -1588,7 +1588,7 @@ retry: ret = parse_cgroupfs_options(data, &opts); if (ret) goto out_unlock; - +retry: /* look for a matching existing root */ if (!opts.subsys_mask && !opts.none && !opts.name) { cgrp_dfl_root_visible = true; @@ -1647,9 +1647,9 @@ retry: if (!atomic_inc_not_zero(&root->cgrp.refcnt)) { mutex_unlock(&cgroup_mutex); mutex_unlock(&cgroup_tree_mutex); - kfree(opts.release_agent); - kfree(opts.name); msleep(10); + mutex_lock(&cgroup_tree_mutex); + mutex_lock(&cgroup_mutex); goto retry; } -- 1.8.0.2 -- 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/