diff options
Diffstat (limited to 'cgroup-fixes.patch')
| -rw-r--r-- | cgroup-fixes.patch | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/cgroup-fixes.patch b/cgroup-fixes.patch deleted file mode 100644 index d0341890..00000000 --- a/cgroup-fixes.patch +++ /dev/null @@ -1,180 +0,0 @@ -Bugzilla: 1045775 -Upstream-status: queued for 3.14-rc3 and stable 3.12+ - -Path: news.gmane.org!not-for-mail -From: Michal Hocko <mhocko@suse.cz> -Newsgroups: gmane.linux.kernel,gmane.linux.kernel.cgroups -Subject: Re: [PATCH] cgroup: protect modifications to cgroup_idr with - cgroup_mutex -Date: Wed, 12 Feb 2014 10:12:38 +0100 -Lines: 127 -Approved: news@gmane.org -Message-ID: <20140212091238.GC28085@dhcp22.suse.cz> -References: <52F9D9DA.7040108@huawei.com> - <20140211102032.GA11946@dhcp22.suse.cz> -NNTP-Posting-Host: plane.gmane.org -Mime-Version: 1.0 -Content-Type: text/plain; charset=us-ascii -X-Trace: ger.gmane.org 1392196376 529 80.91.229.3 (12 Feb 2014 09:12:56 GMT) -X-Complaints-To: usenet@ger.gmane.org -NNTP-Posting-Date: Wed, 12 Feb 2014 09:12:56 +0000 (UTC) -Cc: Tejun Heo <tj@kernel.org>, LKML <linux-kernel@vger.kernel.org>, - Cgroups <cgroups@vger.kernel.org> -To: Li Zefan <lizefan@huawei.com> -Original-X-From: linux-kernel-owner@vger.kernel.org Wed Feb 12 10:13:03 2014 -Return-path: <linux-kernel-owner@vger.kernel.org> -Envelope-to: glk-linux-kernel-3@plane.gmane.org -Original-Received: from vger.kernel.org ([209.132.180.67]) - by plane.gmane.org with esmtp (Exim 4.69) - (envelope-from <linux-kernel-owner@vger.kernel.org>) - id 1WDVsM-0003po-4o - for glk-linux-kernel-3@plane.gmane.org; Wed, 12 Feb 2014 10:13:02 +0100 -Original-Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand - id S1751758AbaBLJMs (ORCPT <rfc822;glk-linux-kernel-3@m.gmane.org>); - Wed, 12 Feb 2014 04:12:48 -0500 -Original-Received: from cantor2.suse.de ([195.135.220.15]:34766 "EHLO mx2.suse.de" - rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP - id S1750890AbaBLJMk (ORCPT <rfc822;linux-kernel@vger.kernel.org>); - Wed, 12 Feb 2014 04:12:40 -0500 -Original-Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) - by mx2.suse.de (Postfix) with ESMTP id 216F1ABB2; - Wed, 12 Feb 2014 09:12:39 +0000 (UTC) -Content-Disposition: inline -In-Reply-To: <20140211102032.GA11946@dhcp22.suse.cz> -User-Agent: Mutt/1.5.21 (2010-09-15) -Original-Sender: linux-kernel-owner@vger.kernel.org -Precedence: bulk -List-ID: <linux-kernel.vger.kernel.org> -X-Mailing-List: linux-kernel@vger.kernel.org -Xref: news.gmane.org gmane.linux.kernel:1646465 gmane.linux.kernel.cgroups:10357 -Archived-At: <http://permalink.gmane.org/gmane.linux.kernel/1646465> - -Li has pointed out that my previous backport was not correct because -err_unlock label releases a reference to supperblock which was not taken -before idr_alloc. I've also removed cgroup_mutex from free_css_id as per -Li. -Fixed in this version. - ---- -Date: Tue, 11 Feb 2014 16:05:46 +0800 -From: Li Zefan <lizefan@huawei.com> -Subject: [PATCH - for 3.12] cgroup: protect modifications to cgroup_idr with cgroup_mutex - -Setup cgroupfs like this: - # mount -t cgroup -o cpuacct xxx /cgroup - # mkdir /cgroup/sub1 - # mkdir /cgroup/sub2 - -Then run these two commands: - # for ((; ;)) { mkdir /cgroup/sub1/tmp && rmdir /mnt/sub1/tmp; } & - # for ((; ;)) { mkdir /cgroup/sub2/tmp && rmdir /mnt/sub2/tmp; } & - -After seconds you may see this warning: - -------------[ cut here ]------------ -WARNING: CPU: 1 PID: 25243 at lib/idr.c:527 sub_remove+0x87/0x1b0() -idr_remove called for id=6 which is not allocated. -... -Call Trace: - [<ffffffff8156063c>] dump_stack+0x7a/0x96 - [<ffffffff810591ac>] warn_slowpath_common+0x8c/0xc0 - [<ffffffff81059296>] warn_slowpath_fmt+0x46/0x50 - [<ffffffff81300aa7>] sub_remove+0x87/0x1b0 - [<ffffffff810f3f02>] ? css_killed_work_fn+0x32/0x1b0 - [<ffffffff81300bf5>] idr_remove+0x25/0xd0 - [<ffffffff810f2bab>] cgroup_destroy_css_killed+0x5b/0xc0 - [<ffffffff810f4000>] css_killed_work_fn+0x130/0x1b0 - [<ffffffff8107cdbc>] process_one_work+0x26c/0x550 - [<ffffffff8107eefe>] worker_thread+0x12e/0x3b0 - [<ffffffff81085f96>] kthread+0xe6/0xf0 - [<ffffffff81570bac>] ret_from_fork+0x7c/0xb0 ----[ end trace 2d1577ec10cf80d0 ]--- - -It's because allocating/removing cgroup ID is not properly synchronized. - -The bug was introduced when we converted cgroup_ida to cgroup_idr. -While synchronization is already done inside ida_simple_{get,remove}(), -users are responsible for concurrent calls to idr_{alloc,remove}(). - -[mhocko@suse.cz: ported to 3.12] -Fixes: 4e96ee8e981b ("cgroup: convert cgroup_ida to cgroup_idr") -Cc: <stable@vger.kernel.org> #3.12+ -Reported-by: Michal Hocko <mhocko@suse.cz> -Signed-off-by: Li Zefan <lizefan@huawei.com> -Signed-off-by: Michal Hocko <mhocko@suse.cz> ---- - include/linux/cgroup.h | 2 ++ - kernel/cgroup.c | 23 ++++++++++++----------- - 2 files changed, 14 insertions(+), 11 deletions(-) - ---- a/include/linux/cgroup.h -+++ b/include/linux/cgroup.h -@@ -169,6 +169,8 @@ struct cgroup { - * - * The ID of the root cgroup is always 0, and a new cgroup - * will be assigned with a smallest available ID. -+ * -+ * Allocating/Removing ID must be protected by cgroup_mutex. - */ - int id; - ---- a/kernel/cgroup.c -+++ b/kernel/cgroup.c -@@ -4410,16 +4410,6 @@ static long cgroup_create(struct cgroup - rcu_assign_pointer(cgrp->name, name); - - /* -- * Temporarily set the pointer to NULL, so idr_find() won't return -- * a half-baked cgroup. -- */ -- cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL); -- if (cgrp->id < 0) { -- err = -ENOMEM; -- goto err_free_name; -- } -- -- /* - * Only live parents can have children. Note that the liveliness - * check isn't strictly necessary because cgroup_mkdir() and - * cgroup_rmdir() are fully synchronized by i_mutex; however, do it -@@ -4426,7 +4418,7 @@ static long cgroup_create(struct cgroup - */ - if (!cgroup_lock_live_group(parent)) { - err = -ENODEV; -- goto err_free_id; -+ goto err_free_name; - } - - /* Grab a reference on the superblock so the hierarchy doesn't -@@ -4436,6 +4428,14 @@ static long cgroup_create(struct cgroup - * fs */ - atomic_inc(&sb->s_active); - -+ /* -+ * Temporarily set the pointer to NULL, so idr_find() won't return -+ * a half-baked cgroup. -+ */ -+ cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL); -+ if (cgrp->id < 0) -+ goto err_unlock; -+ - init_cgroup_housekeeping(cgrp); - - dentry->d_fsdata = cgrp; -@@ -4542,11 +4542,11 @@ err_free_all: - ss->css_free(css); - } - } -+ idr_remove(&root->cgroup_idr, cgrp->id); -+err_unlock: - mutex_unlock(&cgroup_mutex); - /* Release the reference count that we took on the superblock */ - deactivate_super(sb); --err_free_id: -- idr_remove(&root->cgroup_idr, cgrp->id); - err_free_name: - kfree(rcu_dereference_raw(cgrp->name)); - err_free_cgrp: --- -Michal Hocko -SUSE Labs |