From: Jens Axboe <axboe@kernel.dk>
To: Tejun Heo <tj@kernel.org>, Tahsin Erdogan <tahsin@google.com>
Cc: cgroups@vger.kernel.org, "Theodore Ts'o" <tytso@mit.edu>,
Nauman Rafique <nauman@google.com>,
linux-kernel@vger.kernel.org, Jan Kara <jack@suse.com>
Subject: Re: [PATCH block/for-4.5-fixes] writeback: keep superblock pinned during cgroup writeback association switches
Date: Tue, 16 Feb 2016 11:34:33 -0700 [thread overview]
Message-ID: <56C36BB9.5000104@kernel.dk> (raw)
In-Reply-To: <20160216182457.GO3741@mtj.duckdns.org>
On 02/16/2016 11:24 AM, Tejun Heo wrote:
> From 586afaa034bec88934bad4eb6ab38ba07031ec5a Mon Sep 17 00:00:00 2001
> From: Tejun Heo <tj@kernel.org>
> Date: Tue, 16 Feb 2016 13:14:35 -0500
>
> If cgroup writeback is in use, an inode is associated with a cgroup
> for writeback. If the inode's main dirtier changes to another cgroup,
> the association gets updated asynchronously. Nothing was pinning the
> superblock while such switches are in progress and superblock could go
> away while async switching is pending or in progress leading to
> crashes like the following.
>
> kernel BUG at fs/jbd2/transaction.c:319!
> invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
> CPU: 1 PID: 29158 Comm: kworker/1:10 Not tainted 4.5.0-rc3 #51
> Hardware name: Google Google, BIOS Google 01/01/2011
> Workqueue: events inode_switch_wbs_work_fn
> task: ffff880213dbbd40 ti: ffff880209264000 task.ti: ffff880209264000
> RIP: 0010:[<ffffffff803e6922>] [<ffffffff803e6922>] start_this_handle+0x382/0x3e0
> RSP: 0018:ffff880209267c30 EFLAGS: 00010202
> ...
> Call Trace:
> [<ffffffff803e6be4>] jbd2__journal_start+0xf4/0x190
> [<ffffffff803cfc7e>] __ext4_journal_start_sb+0x4e/0x70
> [<ffffffff803b31ec>] ext4_evict_inode+0x12c/0x3d0
> [<ffffffff8035338b>] evict+0xbb/0x190
> [<ffffffff80354190>] iput+0x130/0x190
> [<ffffffff80360223>] inode_switch_wbs_work_fn+0x343/0x4c0
> [<ffffffff80279819>] process_one_work+0x129/0x300
> [<ffffffff80279b16>] worker_thread+0x126/0x480
> [<ffffffff8027ed14>] kthread+0xc4/0xe0
> [<ffffffff809771df>] ret_from_fork+0x3f/0x70
>
> Fix it by bumping s_active while cgroup association switching is in
> flight.
Added for 4.5.
--
Jens Axboe
next prev parent reply other threads:[~2016-02-16 18:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com>
[not found] ` <20160215210047.GN3965@htj.duckdns.org>
[not found] ` <CAAeU0aNAd1Ra6LXmWwq8row4MD_BpVHiSXOwHx07m86UWREvHw@mail.gmail.com>
2016-02-16 18:24 ` Tejun Heo
2016-02-16 18:34 ` Jens Axboe [this message]
2016-02-17 20:57 ` Jan Kara
2016-02-17 21:07 ` Tejun Heo
2016-02-17 22:30 ` Jan Kara
2016-02-17 22:41 ` Tahsin Erdogan
2016-02-17 23:02 ` Tejun Heo
2016-02-18 9:55 ` Jan Kara
2016-02-18 13:00 ` Tejun Heo
2016-02-18 13:20 ` Jan Kara
2016-02-19 20:18 ` Al Viro
2016-02-19 20:51 ` Tejun Heo
2016-02-19 21:58 ` Al Viro
2016-02-19 22:15 ` Tejun Heo
2016-02-19 22:26 ` Al Viro
2016-02-28 21:53 ` Tejun Heo
2016-02-29 20:47 ` [PATCH block/for-linus] writeback: flush inode cgroup wb switches instead of pinning super_block Tejun Heo
2016-02-29 20:54 ` Al Viro
2016-02-29 20:58 ` Tejun Heo
2016-02-29 21:06 ` Al Viro
2016-02-29 21:08 ` Tejun Heo
2016-02-29 21:21 ` Jan Kara
2016-02-29 23:28 ` [PATCH v2 " Tejun Heo
2016-03-01 9:20 ` Jan Kara
2016-03-01 17:46 ` Jens Axboe
2016-03-01 17:50 ` Tejun Heo
2016-03-02 10:29 ` Jan Kara
2016-03-01 13:39 ` [PATCH " Tahsin Erdogan
2016-02-18 10:12 ` [PATCH block/for-4.5-fixes] writeback: keep superblock pinned during cgroup writeback association switches Nikolay Borisov
2016-02-18 12:57 ` Tejun Heo
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