From: Tejun Heo <tj@kernel.org>
To: Peter Wu <lekensteyn@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Kernel development list <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] writeback: fix NULL dereference when device is gone
Date: Mon, 19 Aug 2013 19:02:40 -0400 [thread overview]
Message-ID: <20130819230240.GA6869@mtj.dyndns.org> (raw)
In-Reply-To: <5177367.3UXkd1Z6lS@al>
On Tue, Aug 20, 2013 at 12:45:53AM +0200, Peter Wu wrote:
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 68851ff..6e38a8b 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -1007,7 +1007,8 @@ void bdi_writeback_workfn(struct work_struct *work)
> struct backing_dev_info *bdi = wb->bdi;
> long pages_written;
>
> - set_worker_desc("flush-%s", dev_name(bdi->dev));
> + if (bdi->dev)
> + set_worker_desc("flush-%s", dev_name(bdi->dev));
Hmmm... bdi->dev is cleared after bdi_wb_shutdown() so the work item
should no longer be running. It seems like something is queueing the
work item after shutdown and the proper fix would be finding out which
and fixing it. Can you please verify whether adding
WARN_ON(!bdi->dev) in bdi_wakeup_thread_delayed() trigger anything?
Thanks.
--
tejun
next prev parent reply other threads:[~2013-08-19 23:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-18 1:08 [3.11-rc5..] NULL pointer dereference in bdi_writeback_workfn Alan Stern
2013-08-19 22:45 ` [PATCH] writeback: fix NULL dereference when device is gone Peter Wu
2013-08-19 23:02 ` Tejun Heo [this message]
2013-08-20 10:13 ` Peter Wu
2013-08-20 13:33 ` Tejun Heo
2013-08-28 22:31 ` Peter Wu
2013-09-04 18:21 ` Tejun Heo
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