Re: [REGRESSION] v5.17-rc1+: FIFREEZE ioctl system call hangs

From: Thomas Deutschmann <whissi@whissi.de>
To: Song Liu <song@kernel.org>
Cc: Vishal Verma <vverma@digitalocean.com>,
	Thorsten Leemhuis <regressions@leemhuis.info>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
	Jens Axboe <axboe@kernel.dk>
Subject: Re: [REGRESSION] v5.17-rc1+: FIFREEZE ioctl system call hangs
Date: Mon, 22 Aug 2022 18:30:31 +0200	[thread overview]
Message-ID: <4f69659f-7160-7854-0ed5-6867e3eb2edb@whissi.de> (raw)
In-Reply-To: <b903abd4-d101-e6a5-06a0-667853286308@whissi.de>

Hi,

I can now reproduce using fio:

I looked around in MariaDB issue tracker and found 
https://jira.mariadb.org/browse/MDEV-26674 which lead me to 
https://github.com/MariaDB/server/commit/de7db5517de11a58d57d2a41d0bc6f38b6f92dd8 
-- it's a conditional based on $KV and I hit that kernel regression 
during one of my bisect attempts (see 
https://lore.kernel.org/all/701f3fc0-2f0c-a32c-0d41-b489a9a59b99@whissi.de/).

Setting innodb_use_native_aio=OFF will prevent the problem.

This helped me to find https://github.com/axboe/fio/issues/1195 so I now 
have a working reproducer for fio.

   $ cat reproducer.fio
   [global]
   direct=1
   thread=1
   norandommap=1
   group_reporting=1
   time_based=1
   ioengine=io_uring

   rw=randwrite
   bs=4096
   runtime=20
   numjobs=1
   fixedbufs=1
   hipri=1
   registerfiles=1
   sqthread_poll=1

   [filename0]
   directory=/srv/machines/fio
   size=200M
   iodepth=1
   cpus_allowed=20

...now call fio like "fio reproducer.fio". After one successful fio run, 
fsfreeze will already hang for me.

-- 
Regards,
Thomas