From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ph.de-nserver.de ([85.158.179.214]:37933 "EHLO mail-ph.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264AbbIAElT (ORCPT ); Tue, 1 Sep 2015 00:41:19 -0400 Subject: Re: btrfs regression since 4.X kernel NULL pointer dereference To: Chris Mason , Christoph Hellwig , "linux-btrfs@vger.kernel.org" , "" References: <55D8B193.8010906@profihost.ag> <20150825090030.GF31630@lst.de> <20150825135146.GE7176@ret.masoncoding.com> <590FB3C7-8BCA-4B04-BBB0-92863E02A89C@profihost.ag> <20150901000610.GC5136@ret.masoncoding.com> From: Stefan Priebe Message-ID: <55E52C6D.6050504@profihost.ag> Date: Tue, 1 Sep 2015 06:41:17 +0200 MIME-Version: 1.0 In-Reply-To: <20150901000610.GC5136@ret.masoncoding.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am 01.09.2015 um 02:06 schrieb Chris Mason: > On Mon, Aug 31, 2015 at 07:32:09PM +0200, Stefan Priebe - Profihost AG wrote: >>> Am 25.08.2015 um 15:51 schrieb Chris Mason : >>> >>>> On Tue, Aug 25, 2015 at 11:00:30AM +0200, Christoph Hellwig wrote: >>>> I think this is btrfs using a struct block_device that doesn't have >>>> a valid queue pointer in it's gendisk for ->s_bdev. And there are >>>> some fishy looking ->s_bdev assignments in the code which I suspect >>>> are related to it: >>>> >>>> fs/btrfs/dev-replace.c: if (fs_info->sb->s_bdev == src_device->bdev) >>>> fs/btrfs/dev-replace.c: fs_info->sb->s_bdev = tgt_device->bdev; >>>> fs/btrfs/volumes.c: if (device->bdev == root->fs_info->sb->s_bdev) >>>> fs/btrfs/volumes.c: root->fs_info->sb->s_bdev = next_device->bdev; >>>> fs/btrfs/volumes.c: if (tgtdev->bdev == fs_info->sb->s_bdev) >>>> fs/btrfs/volumes.c: fs_info->sb->s_bdev = next_device->bdev; >>> >>> We've had trouble with this in the past, I'll take a look. >> >> Any news? > > Haven't been able to reproduce yet, I'll try again in the morning. Thanks. We're using schroot like the user in this bugreport: https://bugzilla.kernel.org/show_bug.cgi?id=100911 But he also claims he found another way to reproduce using vfcgbackup (last comment). Stefan > > -chris >