Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754163AbdCIJZy (ORCPT <rfc822;w@1wt.eu>);
        Thu, 9 Mar 2017 04:25:54 -0500
Received: from szxga02-in.huawei.com ([45.249.212.188]:3853 "EHLO
        dggrg02-dlp.huawei.com" rhost-flags-OK-FAIL-OK-FAIL)
        by vger.kernel.org with ESMTP id S1753712AbdCIJZv (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 9 Mar 2017 04:25:51 -0500
Subject: Re: cgroup: WARNING in cgroup_kill_sb
To: Dmitry Vyukov <dvyukov@google.com>, Tejun Heo <tj@kernel.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>, <jweiner@fb.com>,
        LKML <linux-kernel@vger.kernel.org>, Al Viro <viro@zeniv.linux.org.uk>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
References: <CACT4Y+Y9d3FwPWR+pVNMU1uho9GYwJ6gfJ7AjE+NXYoA0py4ow@mail.gmail.com>
CC: syzkaller <syzkaller@googlegroups.com>
From: Zefan Li <lizefan@huawei.com>
Message-ID: <58C11F61.1090804@huawei.com>
Date: Thu, 9 Mar 2017 17:24:49 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <CACT4Y+Y9d3FwPWR+pVNMU1uho9GYwJ6gfJ7AjE+NXYoA0py4ow@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
X-Originating-IP: [10.177.19.236]
X-CFilter-Loop: Reflected
X-Mirapoint-Virus-RAPID-Raw: score=unknown(0),
        refid=str=0001.0A020201.58C11F6A.025C,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0,
        ip=0.0.0.0,
        so=2014-11-16 11:51:01,
        dmn=2013-03-21 17:37:32
X-Mirapoint-Loop-Id: f5983f5e308c15e98af8fd2144a66dbc
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2170
Lines: 45

On 2017/3/3 3:15, Dmitry Vyukov wrote:
> Hello,
> 
> The following program triggers WARNING in cgroup_kill_sb:
> https://gist.githubusercontent.com/dvyukov/47a37d3b899ece1f57e512dc6c90bca6/raw/250894f3d6e2954eed01bac39e4c3b7ec59a9c31/gistfile1.txt
> 
> 
> WARNING: CPU: 2 PID: 3092 at lib/percpu-refcount.c:317
> percpu_ref_kill_and_confirm+0x3ff/0x4f0 lib/percpu-refcount.c:316
> percpu_ref_kill_and_confirm called more than once on css_release!
> Kernel panic - not syncing: panic_on_warn set ...
> 
> CPU: 2 PID: 3092 Comm: a.out Not tainted 4.10.0+ #260
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:15 [inline]
>  dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
>  panic+0x1fb/0x412 kernel/panic.c:179
>  __warn+0x1c4/0x1e0 kernel/panic.c:540
>  warn_slowpath_fmt+0xc5/0x100 kernel/panic.c:563
>  percpu_ref_kill_and_confirm+0x3ff/0x4f0 lib/percpu-refcount.c:316
>  percpu_ref_kill include/linux/percpu-refcount.h:119 [inline]
>  cgroup_kill_sb+0x188/0x530 kernel/cgroup/cgroup.c:1833
>  deactivate_locked_super+0x88/0xd0 fs/super.c:309
>  deactivate_super+0x155/0x1b0 fs/super.c:340
>  cleanup_mnt+0xb2/0x160 fs/namespace.c:1112
>  __cleanup_mnt+0x16/0x20 fs/namespace.c:1119
>  task_work_run+0x18a/0x260 kernel/task_work.c:116
>  tracehook_notify_resume include/linux/tracehook.h:191 [inline]
>  exit_to_usermode_loop+0x23b/0x2a0 arch/x86/entry/common.c:160
>  prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
>  syscall_return_slowpath+0x4d3/0x570 arch/x86/entry/common.c:259
>  entry_SYSCALL_64_fastpath+0xc0/0xc2
> RIP: 0033:0x440b39
> RSP: 002b:00007f3e8bd0cdb8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffec RBX: 0000000000000000 RCX: 0000000000440b39
> RDX: 00000000004a0f3b RSI: 00000000004a0f34 RDI: 00000000004a0f34
> RBP: 00007f3e8bd0cdd0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000005 R11: 0000000000000202 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f3e8bd0d9c0 R15: 00007f3e8bd0d700
> 
> On commit 4977ab6e92e267afe9d8f78438c3db330ca8434c
> .

could you share your kernel config? I can't reproduce this bug.