On Sat, Dec 9, 2017 at 7:27 AM, Michele Ballabio
[off-list ref] wrote:

On Fri, 8 Dec 2017 13:08:37 -0700
Jens Axboe [off-list ref] wrote:

quoted

On 12/08/2017 08:38 AM, Michele Ballabio wrote:

quoted

Hi,
    kernels 4.13.*, 4.14.* 4.15-rc2 crash on occasion,
especially on x86-32 systems. To trigger the problem, run as root:

while true
do
        /sbin/udevadm trigger --type=subsystems --action=change
        /sbin/udevadm trigger --type=devices --action=change
        /sbin/udevadm settle --timeout=120
done

(Thanks to Patrick Volkerding for the reproducer).

Sometimes the kernel oopses immediately, sometimes a bit later
(less than five minutes).

The bisection pointed to commit
caa4b02476e31fc7933d2138062f7f355d3cd8f7 (blk-map: call
blk_queue_bounce from blk_rq_append_bio). A revert fixes the
problem (tested on 4.13 and master).

Thanks for your report - can you try the below patch? Totally
untested...

I applied the patch on master
(968edbd93c0cbb40ab48aca972392d377713a0c3), I tried two times to boot
the system but couldn't get to the shell. I found this in the log:

Hi Michele,

Please test the patches I sent out and see if it fixes your issue. In
my environment
the two just works fine.

https://marc.info/?l=linux-block&m=151358285916762&w=2

-- 
Ming Lei