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

[Jens Axboe <axboe@xxxxxxxxx>]

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?

-- 
Jens Axboe