From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752211Ab3LGH6S (ORCPT ); Sat, 7 Dec 2013 02:58:18 -0500 Received: from relay.parallels.com ([195.214.232.42]:46411 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751607Ab3LGH6Q (ORCPT ); Sat, 7 Dec 2013 02:58:16 -0500 From: Vladimir Davydov To: CC: , , Tejun Heo , Li Zefan Subject: [PATCH] cgroup: fix fail path in cgroup_load_subsys() Date: Sat, 7 Dec 2013 11:58:05 +0400 Message-ID: <1386403085-24866-1-git-send-email-vdavydov@parallels.com> X-Mailer: git-send-email 1.7.10.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.24.25.78] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should not call cgroup_unload_subsys() if online_css() fails, because online_css() does not assign css to cgroup on failure, while offline_css() called from cgroup_unload_subsys() expects it is assigned. So let's call everything we need to rollback inline without involving cgroup_unload_subsys(). Signed-off-by: Vladimir Davydov Cc: Tejun Heo Cc: Li Zefan --- kernel/cgroup.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 8b729c2..3cd7247 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4861,10 +4861,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) */ css = ss->css_alloc(cgroup_css(cgroup_dummy_top, ss)); if (IS_ERR(css)) { - /* failure case - need to deassign the cgroup_subsys[] slot. */ - cgroup_subsys[ss->subsys_id] = NULL; - mutex_unlock(&cgroup_mutex); - return PTR_ERR(css); + ret = PTR_ERR(css); + goto out_err; } list_add(&ss->sibling, &cgroup_dummy_root.subsys_list); @@ -4873,6 +4871,10 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) /* our new subsystem will be attached to the dummy hierarchy. */ init_css(css, ss, cgroup_dummy_top); + ret = online_css(css); + if (ret) + goto free_css; + /* * Now we need to entangle the css into the existing css_sets. unlike * in cgroup_init_subsys, there are now multiple css_sets, so each one @@ -4896,18 +4898,17 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) } write_unlock(&css_set_lock); - ret = online_css(css); - if (ret) - goto err_unload; - /* success! */ mutex_unlock(&cgroup_mutex); return 0; -err_unload: +free_css: + list_del(&ss->sibling); + ss->css_free(css); +out_err: + /* failure case - need to deassign the cgroup_subsys[] slot. */ + cgroup_subsys[ss->subsys_id] = NULL; mutex_unlock(&cgroup_mutex); - /* @ss can't be mounted here as try_module_get() would fail */ - cgroup_unload_subsys(ss); return ret; } EXPORT_SYMBOL_GPL(cgroup_load_subsys); -- 1.7.10.4