From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-fsdevel-owner@vger.kernel.org>
Received: from mail.kernel.org ([198.145.29.99]:42648 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1727141AbeHOPgH (ORCPT <rfc822;linux-fsdevel@vger.kernel.org>);
        Wed, 15 Aug 2018 11:36:07 -0400
Message-ID: <1eccaca5ea2ae8e5d32ef44d92e893ad870e754d.camel@kernel.org>
Subject: Re: [BUG][BISECT] NFSv4 root failures after "fs/locks: allow a lock
 request to block other requests."
From: Jeff Layton <jlayton@kernel.org>
To: Krzysztof Kozlowski <krzk@kernel.org>, NeilBrown <neilb@suse.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
        "J. Bruce Fields" <bfields@fieldses.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        "linux-samsung-soc@vger.kernel.org"
        <linux-samsung-soc@vger.kernel.org>
Date: Wed, 15 Aug 2018 08:44:03 -0400
In-Reply-To: <CAJKOXPc2cb1OK3tmRCO2p+docdXY=PoU1MEBa-VDyEM4mG1eSw@mail.gmail.com>
References: <CAJKOXPc2cb1OK3tmRCO2p+docdXY=PoU1MEBa-VDyEM4mG1eSw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

On Wed, 2018-08-15 at 14:28 +0200, Krzysztof Kozlowski wrote:
> Hi,
> 
> Bisect pointed commit ce3147990450a68b3f549088b30f087742a08b5d
> ("fs/locks: allow a lock request to block other requests.") to failure
> boot of NFSv4 with root on several boards.
> 
> Log is here:
> https://krzk.eu/#/builders/21/builds/836/steps/12/logs/serial0
> 
> With several errors:
> kernel BUG at ../fs/locks.c:336!
> Unable to handle kernel NULL pointer dereference at virtual address 00000004
> 
> Configuration:
> 1. exynos_defconfig
> 2. Arch ARM Linux
> 3. Boards:
> a. Odroid family (ARMv7, octa-core (Cortex-A7+A15), Exynos5422 SoC)
> b. Toradex Colibri VF50 (ARMv7, UP, Cortex-A5)
> 4. Systemd: v236, 238
> 5. All boards boot from TFTP with NFS root (NFSv4)
> 
> On Colibri VF50 I got slightly different errors:
> [   11.663204] Internal error: Oops - undefined instruction: 0 [#1] ARM
> [   12.455273] Unable to handle kernel NULL pointer dereference at
> virtual address 00000004
> and only with some specific GCC (v6.3) or with other conditions which
> I did not bisect yet. Maybe Colibri's failure is unrelated to that
> commit.
> 
> Best regards,
> Krzysztof

Thanks Krzysztof,

I or Neil will see if this is reproducible and see about coming up with
a fix. For now, I'll take this out of -next.

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>