Re: [LKP] a9f38e1dec [ 245.678853] INFO: task mount:580 blocked for more than 120 seconds.

[Jens Axboe]

On 11/6/18 8:16 PM, kernel test robot wrote:
> Greetings,
> 
> 0day kernel testing robot got the below dmesg and the first bad commit is
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> 
> commit a9f38e1dec107af70d81338332494bf0a1e76597
> Author:     Omar Sandoval <osandov@xxxxxx>
> AuthorDate: Mon Oct 15 09:21:34 2018 -0600
> Commit:     Jens Axboe <axboe@xxxxxxxxx>
> CommitDate: Tue Oct 16 09:50:14 2018 -0600
> 
>     floppy: convert to blk-mq
>     
>     This driver likes to fetch requests from all over the place, so make
>     queue_rq put requests on a list so that the logic stays the same. Tested
>     with QEMU.
>     
>     Signed-off-by: Omar Sandoval <osandov@xxxxxx>
>     
>     Converted to blk_mq_init_sq_queue() and fixed a few spots where the
>     tag_set leaked on cleanup.
>     
>     Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>

I don't think this is the reason for the hang, I think it just exposed
it. I posted a patch to fix this, hopefully, it's included below as
well. Can you give it a try?