From: Nikos Tsironis <ntsironis@arrikto.com>
To: Mike Snitzer <snitzer@redhat.com>,
Guruswamy Basavaiah <guru2018@gmail.com>
Cc: dm-devel@redhat.com, agk@redhat.com, iliastsi@arrikto.com
Subject: Re: Fix "dm kcopyd: Fix bug causing workqueue stalls" causes dead lock
Date: Wed, 9 Oct 2019 18:44:49 +0300 [thread overview]
Message-ID: <d6aaebd8-ed3e-2e6a-14ea-33bf023ee4bb@arrikto.com> (raw)
In-Reply-To: <20191009141308.GA1670@redhat.com>
On 10/9/19 5:13 PM, Mike Snitzer wrote:> On Tue, Oct 01 2019 at 8:43am -0400,
> Nikos Tsironis <ntsironis@arrikto.com> wrote:
>
>> On 10/1/19 3:27 PM, Guruswamy Basavaiah wrote:
>>> Hello Nikos,
>>> Yes, issue is consistently reproducible with us, in a particular
>>> set-up and test case.
>>> I will get the access to set-up next week, will try to test and let
>>> you know the results before end of next week.
>>>
>>
>> That sounds great!
>>
>> Thanks a lot,
>> Nikos
>
> Hi Guru,
>
> Any chance you could try this fix that I've staged to send to Linus?
> https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.4&id=633b1613b2a49304743c18314bb6e6465c21fd8a
>
> Shiort of that, Nikos: do you happen to have a test scenario that teases
> out this deadlock?
>
Hi Mike,
Yes,
I created a 50G LV and took a snapshot of the same size:
lvcreate -n data-lv -L50G testvg
lvcreate -n snap-lv -L50G -s testvg/data-lv
Then I ran the following fio job:
[global]
randrepeat=1
ioengine=libaio
bs=1M
size=6G
offset_increment=6G
numjobs=8
direct=1
iodepth=32
group_reporting
filename=/dev/testvg/data-lv
[test]
rw=write
timeout=180
, concurrently with the following script:
lvcreate -n dummy-lv -L1G testvg
while true
do
lvcreate -n dummy-snap -L1M -s testvg/dummy-lv
lvremove -f testvg/dummy-snap
done
This reproduced the deadlock for me. I also ran 'echo 30 >
/proc/sys/kernel/hung_task_timeout_secs', to reduce the hung task
timeout.
Nikos.
> Thanks,
> Mike
>
next prev parent reply other threads:[~2019-10-09 15:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 13:19 Fix "dm kcopyd: Fix bug causing workqueue stalls" causes dead lock Guruswamy Basavaiah
2019-09-27 19:33 ` Nikos Tsironis
2019-09-29 14:36 ` Guruswamy Basavaiah
2019-10-01 12:12 ` Nikos Tsironis
2019-10-01 12:27 ` Guruswamy Basavaiah
2019-10-01 12:43 ` Nikos Tsironis
2019-10-09 14:13 ` Mike Snitzer
2019-10-09 15:44 ` Nikos Tsironis [this message]
2019-10-09 16:04 ` Mike Snitzer
2019-10-09 20:03 ` Guruswamy Basavaiah
2019-10-10 6:34 ` Guruswamy Basavaiah
2019-10-10 12:03 ` Nikos Tsironis
2019-10-11 10:17 ` Guruswamy Basavaiah
2019-10-11 11:39 ` Nikos Tsironis
2019-10-11 12:17 ` Nikos Tsironis
2019-10-12 8:46 ` Guruswamy Basavaiah
2019-10-17 5:58 ` Guruswamy Basavaiah
2019-10-17 7:43 ` Nikos Tsironis
2019-10-10 11:58 ` Nikos Tsironis
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