Re: 6.0-rc1 regression block (blk_mq) / RCU task stuck errors + block-io hang

[Bart Van Assche]

On 8/19/22 05:01, Hans de Goede wrote:
> I've been dogfooding 6.0-rc1 on my main workstation and I have hit
> this pretty serious bug, serious enough for me to go back to 5.19
>
> My dmesg is showing various blk_mq (RCU?) related lockdep splats
> followed by some tasks getting stuck on disk-IO. E.g. "sync"
> is guaranteed to hang, but other tasks too.
>
> This seems to be mainly the case on "sd" disks (both sata
> and USB) where as my main nvme drive seems fine, which has
> probably saved me from worse issues...
>
> Here are 4 task stuck reports from my last boot, where
> I had to turn off the machine by keeping the power button
> pressed for 4 seconds.
>
> [ ... ]
>
> Sorry for not being able to write a better bug-report but I don't have
> the time to dive into this deeper. I hope this report is enough for
> someone to have a clue what is going on.

Thank you for the detailed report. I think this report is detailed 
enough to root-cause this issue, something that was not possible before 
this report.

Please help with verifying whether this patch fixes this issue: "[PATCH] 
scsi: sd: Revert "Rework asynchronous resume support"" 
(https://lore.kernel.org/linux-scsi/20220816172638.538734-1-bvanassche@xxxxxxx/).

Thanks,

Bart.