From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f42.google.com ([74.125.82.42]:35135 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170AbcGDNPj (ORCPT ); Mon, 4 Jul 2016 09:15:39 -0400 Received: by mail-wm0-f42.google.com with SMTP id z126so41654069wme.0 for ; Mon, 04 Jul 2016 06:15:38 -0700 (PDT) Subject: Re: GPF in __mark_inode_dirty due to locked_inode_to_wb_and_lock_list returning NULL To: Tejun Heo References: <5774FFF6.3030408@kyup.com> <20160701100050.GC22922@quack2.suse.cz> <20160701173827.GE28719@htj.duckdns.org> Cc: Jan Kara , "Linux-Kernel@Vger. Kernel. Org" , dvyukov@google.com, linux-btrfs@vger.kernel.org, SiteGround Operations From: Nikolay Borisov Message-ID: <577A6177.60602@kyup.com> Date: Mon, 4 Jul 2016 16:15:35 +0300 MIME-Version: 1.0 In-Reply-To: <20160701173827.GE28719@htj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 07/01/2016 08:38 PM, Tejun Heo wrote: > On Fri, Jul 01, 2016 at 12:00:50PM +0200, Jan Kara wrote: >> Hello, >> >> On Thu 30-06-16 14:18:14, Nikolay Borisov wrote: >>> In light of the discussion in https://patchwork.kernel.org/patch/9187411/ and >>> the discussion at https://groups.google.com/forum/#!topic/syzkaller/XvxH3cBQ134 >> >> Well, it looks it is also some bdi_writeback lifetime issue but I don't see >> how it would be related to I_DIRTY_TIME issues. There were couple of fixes >> related to bdi_writeback issues from Tejun since 4.4. Maybe Tejun can tell >> you whether he's seen this or not... > > Yeah, this could be the same problem from the blkdev detach path. > Nikolay, was there any block device hot unplugging going on? If not, > do you have a reproducer? So the btrfs fs was created inside a loop device and mounted with -o loop. Evidently from the oops it seems that this is the normal umount path, meaning that no device hot plugging was in action. Unfortunately I don't have a reproducer. However, the workload looks like the following: 1. mount -t btrfs -o compress=zlib -o subvol="${subvol}" -o loop "${storage_file}" "${mount_point}" 2. Do reads/writes (rsync) (dirtying some pages) 3. umount "${mount_point}" > > Thanks. >