On 11/1/21 2:34 AM, Shinichiro Kawasaki wrote:

I tried the latest linux-block/for-next branch tip (git hash b43fadb6631f and
observed a process hang during blktests block/005 run on a NVMe device.
Kernel message reported "INFO: task check:1224 blocked for more than 122
seconds." with call trace [1]. So far, the hang is 100% reproducible with my
system. This hang is not observed with HDDs or null_blk devices.

I bisected and found the commit 4f5022453acd ("nvme: wire up completion batching
for the IRQ path") triggers the hang. When I revert this commit from the
for-next branch tip, the hang disappears. The block/005 test case does IO
scheduler switch during IO, and the completion path change by the commit looks
affecting the scheduler switch. Comments for solution will be appreciated.

I'll take a look at this.

-- 
Jens Axboe