From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752045AbcC0TkK (ORCPT <rfc822;w@1wt.eu>);
	Sun, 27 Mar 2016 15:40:10 -0400
Received: from mail-vk0-f51.google.com ([209.85.213.51]:34469 "EHLO
	mail-vk0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750738AbcC0TkI (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Sun, 27 Mar 2016 15:40:08 -0400
MIME-Version: 1.0
Reply-To: sedat.dilek@gmail.com
In-Reply-To: <20160327182351.GH31129@thunk.org>
References: <CA+icZUVLbBD4xc7OjV112KHhxAnW_t3Fcpjht2SjVAo3Ds-Hrg@mail.gmail.com>
	<CA+icZUXgSK5VY7zJQ0bZZwKZmeYS+A7BRQD2fBBSzK=sM2aMLw@mail.gmail.com>
	<CA+55aFw-YXACVasN4n0h03QWgWWwvBray2fcMScAnEn0Wy_Ohw@mail.gmail.com>
	<20160327182351.GH31129@thunk.org>
Date: Sun, 27 Mar 2016 21:40:07 +0200
Message-ID: <CA+icZUXsM_Uzc5jp-OvbPhqq6x2zV7a5L+30cbhAwq1PL48r1A@mail.gmail.com>
Subject: Re: [Linux-v4.6-rc1] ext4: WARNING: CPU: 2 PID: 2692 at
 kernel/locking/lockdep.c:2017 __lock_acquire+0x180e/0x2260
From: Sedat Dilek <sedat.dilek@gmail.com>
To: "Theodore Ts'o" <tytso@mit.edu>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sedat Dilek <sedat.dilek@gmail.com>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sun, Mar 27, 2016 at 8:23 PM, Theodore Ts'o <tytso@mit.edu> wrote:
> On Sun, Mar 27, 2016 at 05:03:44AM -0700, Linus Torvalds wrote:
>>
>> Unless you're using overlayfs or per-file encryption, I'm not seeing
>> that any of that should make any difference (but it's entirely
>> possible I'm missing something).
>>
>> Was it entirely repeatable before? Maybe it just happened to happen
>> without that update, and then happened to _not_ happen after you
>> rebooted with that 'dev' branch pulled in?
>>
>> Anyway, I don't think that DEBUG_LOCKS_WARN_ON() in
>>
>>   kernel/locking/lockdep.c:2017 __lock_acquire
>>
>> would be an ext4 issue, it looks more like an internal lockdep issue.
>
> That's my guess.  I've been doing a lot of regression testing with
> lockdep enabled, and I haven't seen the problem which Sedat has
> reported.
>
> At the moment I'm testing my ext4 bug fixes on top of 243d5067858310
> (Merge branch 'overlayfs-linus'....) dating from March 22nd, and the
> lockdep merges came much earlier than that, on March 15th, just two
> days after v4.5 was released, and I'm not noticing any lockdep issues
> with ext4 while running all of my regression tests.
>

So far I can say, that I am *not* seeing this with ext4.git#dev on top
of v4.6-rc1.

Not sure how I can force/reproduce the lockdep call-trace.

Any idea on how to check/test lockdep issues like this?
LTP? (Latest tarball: ltp-full-20160126.tar.xz?
xfstests?
xfstests-bld?
Does the linux-sources ship some test-suite?

- Sedat -