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Subject: Re: Bisected GFP in bfq_bfqq_expire on v5.1-rc1
To:     Dmitrii Tcvetkov <demfloro@demfloro.ru>,
        linux-block@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Paolo Valente <paolo.valente@linaro.org>
References: <20190329160227.7d55c8dd@fire.localdomain>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <0e203a26-b941-cef4-dff1-013999d4b041@kernel.dk>
Date:   Fri, 29 Mar 2019 08:10:38 -0600
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On 3/29/19 7:02 AM, Dmitrii Tcvetkov wrote:
> Hi,
> 
> I got kernel panic since v5.1-rc1 when working with files on block
> device with BFQ scheduler assigned. I didn't find trivial way to
> reproduce the panic but "git checkout origin/linux-5.0.y"
> on linux-stable-rc[1] git repo on btrfs filesystem reproduces the
> problem 100% of the time on my bare-metal machine and in a VM.
> 
> Bisect led me to commit 9dee8b3b057e1 (block, bfq: fix queue removal
> from weights tree). After reverting this commit on top of current
> mainline master(9936328b41ce) I can't reproduce the problem.
> 
> dmesg with the panic and bisect log attached.
> 
> [1] https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux-stable-rc.git

Paolo, can you please take a look at this?


-- 
Jens Axboe