Bug 222948

Boot the latest amd64 snapshot either 11 or 12, set the dev= parameter in the script to some available da device and run it. Repeats every time.

LOR panic is almost identical to
http://docs.freebsd.org/cgi/mid.cgi?CAD2Ti2-6W_b04fHen5XHiT-bFQZ9CncZptUbDP0yaHbg7gjnUA
and was possibly first noted here
https://lists.freebsd.org/pipermail/freebsd-stable/2017-June/087291.html

#!/bin/sh --

dev=da1

set -x
dd if=/dev/zero of=/dev/${dev} bs=1m count=64
gpart create -s mbr ${dev}
gpart add -t freebsd -a 1m -b 1m -s 64m -i 1 ${dev}
gpart create -s bsd ${dev}s1
gpart add -t freebsd-ufs -a 1m -b 1m -s 31m -i 1 ${dev}s1
gpart show -p ${dev} ${dev}s1

newfs /dev/${dev}s1a
fsck -fy /dev/${dev}s1a
mount -v -o rw /dev/${dev}s1a /mnt
sysctl kern.geom.debugflags=16
### this is broken, footshooting should be allowed here
# dd: /dev/da0s1: Operation not permitted
dd if=/dev/zero of=/dev/${dev}s1 seek=2  count=1 bs=1m
sysctl kern.geom.debugflags=0
umount -v /dev/${dev}s1a
mount -v -o ro /dev/${dev}s1a /mnt
ls /mnt
dd if=/dev/zero of=/dev/${dev}s1 seek=34 count=1 bs=1m
### this is broken
# ls: .snap: Device not configured
ls -l /mnt
### select mount instead of umount to get the LOR PANIC
umount -v /dev/${dev}s1a
#mount -uvw /dev/${dev}s1a