On 01/13/2017 04:34 PM, Jens Axboe wrote:

On 01/13/2017 08:33 AM, Hannes Reinecke wrote:

[ .. ]

quoted

Ah, indeed.
There is an ominous udev rule here, trying to switch to 'deadline'.

# cat 60-ssd-scheduler.rules
# do not edit this file, it will be overwritten on update

ACTION!="add", GOTO="ssd_scheduler_end"
SUBSYSTEM!="block", GOTO="ssd_scheduler_end"

IMPORT{cmdline}="elevator"
ENV{elevator}=="*?", GOTO="ssd_scheduler_end"

KERNEL=="sd*[!0-9]", ATTR{queue/rotational}=="0",
ATTR{queue/scheduler}="deadline"

LABEL="ssd_scheduler_end"

Still shouldn't crash the kernel, though ...

Of course not, and it's not a given that it does, it could just be
triggering after the device load and failing like expected. But just in
case, can you try and disable that rule and see if it still crashes with
MQ_DEADLINE set as the default?

Yes, it does.
Same stacktrace as before.

Cheers

Hannes
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