Re: md_raid: mdX_raid6 looping after sync_action "check" to "idle" transition

[Yu Kuai <yukuai1@huaweicloud.com>]

Hi,

在 2023/08/30 9:36, Yu Kuai 写道:
> Hi,
> 
> 在 2023/08/29 4:32, Dragan Stancevic 写道:
> 
>> Just a followup on 6.1 testing. I tried reproducing this problem for 5 
>> days with 6.1.42 kernel without your patches and I was not able to 
>> reproduce it.

oops, I forgot that you need to backport this patch first to reporduce
this problem:

https://lore.kernel.org/all/20230529132037.2124527-2-yukuai1@huaweicloud.com/

The patch fix the deadlock as well, but it introduce some regressions.

Thanks,
Kuai

>>
>> It seems that 6.1 has some other code that prevents this from happening.
>>
> 
> I see that there are lots of patches for raid456 between 5.10 and 6.1,
> however, I remember that I used to reporduce the deadlock after 6.1, and
> it's true it's not easy to reporduce, see below:
> 
> https://lore.kernel.org/linux-raid/e9067438-d713-f5f3-0d3d-9e6b0e9efa0e@huaweicloud.com/ 
> 
> 
> My guess is that 6.1 is harder to reporduce than 5.10 due to some
> changes inside raid456.
> 
> By the way, raid10 had a similiar deadlock, and can be fixed the same
> way, so it make sense to backport these patches.
> 
> https://lore.kernel.org/r/20230529132037.2124527-5-yukuai1@huaweicloud.com
> 
> Thanks,
> Kuai
> 
> 
>> On 5.10 I can reproduce it within minutes to an hour.
>>
> 
> .
>