Re: bug in tag handling in blk-mq?

From: Jens Axboe
Date: Tue May 08 2018 - 17:19:37 EST

On 5/8/18 2:37 PM, Jens Axboe wrote:
> On 5/8/18 10:42 AM, Mike Galbraith wrote:
>> On Tue, 2018-05-08 at 08:55 -0600, Jens Axboe wrote:
>>> All the block debug files are empty...
>> Sigh. Take 2, this time cat debug files, having turned block tracing
>> off before doing anything else (so trace bits in dmesg.txt should end
>> AT the stall).
> OK, that's better. What I see from the traces:
> - You have regular IO and some non-fs IO (from scsi_execute()). This mix
> may be key.
> - sdd has nothing pending, yet has 6 active waitqueues.
> I'm going to see if I can reproduce this. Paolo, what kind of attempts
> to reproduce this have you done?

No luck so far. Out of the patches you referenced, I can only find the
shallow depth change, since that's in the parent of this email. Can
you send those as well?

Perhaps also expand a bit on exactly what you are running. File system,
mount options, etc.

Jens Axboe