Hang in blk_mq_freeze_queue_wait()

Hang in blk_mq_freeze_queue_wait()

[Bart Van Assche]

Hi,

If I run test srp/002 against v5.16-rc1 then dmsetup hangs as follows at 
the end of the test:

sysrq: Show Blocked State
task:dmsetup         state:D stack:28136 pid: 3088 ppid:  3087 
flags:0x00004000
Call Trace:
  <TASK>
  __schedule+0x4bd/0xc20
  schedule+0x84/0x140
  blk_mq_freeze_queue_wait+0xf7/0x130
  del_gendisk+0x342/0x410
  cleanup_mapped_device+0x165/0x170 [dm_mod]
  __dm_destroy+0x280/0x450 [dm_mod]
  dm_destroy+0x13/0x20 [dm_mod]
  dev_remove+0x156/0x1d0 [dm_mod]
  ctl_ioctl+0x2bb/0x4d0 [dm_mod]
  dm_ctl_ioctl+0xe/0x20 [dm_mod]
  __x64_sys_ioctl+0xc2/0xe0
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I haven't seen this hang with any previous kernel version. Could this be 
a block layer issue?

v5.16-rc1 includes Ming's commit 10f7335e3627 ("blk-mq: don't grab 
->q_usage_counter in blk_mq_sched_bio_merge").

Thanks,

Bart.

Re: Hang in blk_mq_freeze_queue_wait()

[Jens Axboe]

On 11/16/21 5:15 PM, Bart Van Assche wrote:
> Hi,
> 
> If I run test srp/002 against v5.16-rc1 then dmsetup hangs as follows at 
> the end of the test:
> 
> sysrq: Show Blocked State
> task:dmsetup         state:D stack:28136 pid: 3088 ppid:  3087 
> flags:0x00004000
> Call Trace:
>   <TASK>
>   __schedule+0x4bd/0xc20
>   schedule+0x84/0x140
>   blk_mq_freeze_queue_wait+0xf7/0x130
>   del_gendisk+0x342/0x410
>   cleanup_mapped_device+0x165/0x170 [dm_mod]
>   __dm_destroy+0x280/0x450 [dm_mod]
>   dm_destroy+0x13/0x20 [dm_mod]
>   dev_remove+0x156/0x1d0 [dm_mod]
>   ctl_ioctl+0x2bb/0x4d0 [dm_mod]
>   dm_ctl_ioctl+0xe/0x20 [dm_mod]
>   __x64_sys_ioctl+0xc2/0xe0
>   do_syscall_64+0x35/0x80
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> I haven't seen this hang with any previous kernel version. Could this be 
> a block layer issue?
> 
> v5.16-rc1 includes Ming's commit 10f7335e3627 ("blk-mq: don't grab 
> ->q_usage_counter in blk_mq_sched_bio_merge").

Can you try with:

https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.16&id=95febeb61bf87ca803a1270498cd4cd61554a68f

-- 
Jens Axboe

Re: Hang in blk_mq_freeze_queue_wait()

[Bart Van Assche]

On 11/16/21 16:21, Jens Axboe wrote:
> Can you try with:
> 
> https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.16&id=95febeb61bf87ca803a1270498cd4cd61554a68f

With that patch applied all SRP tests pass. Feel free to add:

Tested-by: Bart Van Assche <bvanassche@acm.org>

Thanks!

Bart.

Re: Hang in blk_mq_freeze_queue_wait()

[Jens Axboe]

On 11/16/21 9:04 PM, Bart Van Assche wrote:
> On 11/16/21 16:21, Jens Axboe wrote:
>> Can you try with:
>>
>> https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.16&id=95febeb61bf87ca803a1270498cd4cd61554a68f
> 
> With that patch applied all SRP tests pass. Feel free to add:
> 
> Tested-by: Bart Van Assche <bvanassche@acm.org>

Thanks for testing! I already pushed this out yesterday morning, so not
going to amend the commit at this point. But at least this conversation
is in the archives.

-- 
Jens Axboe