Re: Bisected GFP in bfq_bfqq_expire on v5.1-rc1

From: Jens Axboe
Date: Fri Mar 29 2019 - 10:10:43 EST


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