On Wed, 2018-08-01 at 21:58 -0700, Guenter Roeck wrote: +AD4- I am running out of ideas. Any thoughts on how to track this down further ? Is a shell available when the hang occurs? If so, it would be helpful if you could provide a dump of the information in /sys/kernel/debug/block. There is namely detailed information in that directory about pending commands. Bart.