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Date: Sun, 24 Oct 2010 22:07:38 +0200
From: Jens Axboe <axboe@kernel.dk>
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To: Milan Broz <mbroz@redhat.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: OOPs on loop module removal
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On 2010-10-24 21:14, Milan Broz wrote:
> 
> 
> Hi,
> Simple modprobe loop ; rmmod loop
> on Linus' tree now produces now OOPS.
> 
> Bisected to patch (and reverting fixes problem)
> 
> commit 7681bfeeccff5efa9eb29bf09249a3c400b15327
> Author: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Date:   Tue Oct 19 09:05:00 2010 +0200
> 
>     block: fix accounting bug on cross partition merges
> 
> The problem is probably that patch uses directly q->queue_lock
> even if queue is being destroyed (QUEUE_FLAG_DEAD is set).
> See what loop (and not only this code) does:
> 
>         blk_cleanup_queue(lo->lo_queue);
> 	put_disk(lo->lo_disk);

Yep that commit was not the most fortunate one. I will send out a revert
now, which will gives us time to fix this for real without rushing
things.

-- 
Jens Axboe