Re: Hang with blk-mq map series (block/008)

[Ming Lei <ming.lei@redhat.com>]

On Tue, Apr 10, 2018 at 08:08:43PM -0600, Jens Axboe wrote:
> On 4/10/18 8:02 PM, Ming Lei wrote:
> > On Tue, Apr 10, 2018 at 09:51:41AM -0600, Jens Axboe wrote:
> >> Hi Ming,
> >>
> >> Ran the above blktests on the current tree, and we end up getting
> >> a hang that we never recover from. There's on request perpetually
> >> stuck:
> >>
> >> root@dell:/sys/kernel/debug/block/nvme0n1/hctx2# cat busy 
> >> 000000005e2b09fe {.op=READ, .cmd_flags=, .rq_flags=DONTPREP|IO_STAT|STATS, .state=in_flight, .tag=313, .internal_tag=-1}
> >>
> >> and no amount of manual running or kicking the queue will bring it
> >> back to life. If I run it on 'master', it works fine.
> >>
> >> Did you run blktests on your series?
> > 
> > Not yet.
> > 
> > Will take a look at it, but this seems related with driver, since
> > the request has been submitted to hardware already.
> 
> It might be, but it repeatedly failed for me on for-linus, and not on
> master. I can try doing some more runs just to gain more confidence.

Looks it is one IO vs CPU hotplug test, which was done before posting.
Not reproduce it on NVMe inside KVM.

Will install a kernel and run it on real HW.

BTW, could you share your lscpu info?

Thanks,
Ming