12.0-ALPHA6-amd64-20180914-r338675 LOR?

Hi,

I am trying out 12.0-ALPHA6-amd64-20180914-r338675 vmdk with a VM with two
CPUs.

When doing "shutdown -h now" I get a lock order reversal, is this expected?

According to https://www.freebsd.org/doc/faq/troubleshoot.html#idp59076936 it
is possible to get false positives from witness.

Attaching output:

root_at_freebsd:~ # shutdown -h now
shutdown -h now
Shutdown NOW!
Sep 17 11:05:04 Stopping cron.
Waiting for PIDS: 676.
Stopping devd.
Waiting for PIDS: 420.
Writing entropy file:.
Writing early boot entropy file:.
Terminated
.
Sep 17 11:05:05 freebsd syslogd: exiting on signal 15
Waiting (max 60 seconds) for system process `vnlru' to stop... done
Waiting (max 60 seconds) for system process `syncer' to stop... 
Syncing disks, vnodes remaining... 2 0 done
Waiting (max 60 seconds) for system thread `bufdaemon' to stop... done
Waiting (max 60 seconds) for system thread `bufspacedaemon-0' to stop... done
All buffers synced.
lock order reversal:
 1st 0xfffff80003702ba8 ufs (ufs) _at_ /usr/src/sys/kern/vfs_mount.c:1343
 2nd 0xfffff80003703248 devfs (devfs) _at_ /usr/src/sys/kern/vfs_subr.c:2590
stack backtrace:
#0 0xffffffff80bf4203 at witness_debugger+0x73
#1 0xffffffff80bf3f53 at witness_checkorder+0xab3
#2 0xffffffff80b60bea at lockmgr_lock_fast_path+0x17a
#3 0xffffffff811df192 at VOP_LOCK1_APV+0xa2
#4 0xffffffff80c6eae0 at _vn_lock+0x60
#5 0xffffffff80c5d5ff at vget+0x5f
#6 0xffffffff80a4646d at devfs_allocv+0xdd
#7 0xffffffff80a45f73 at devfs_root+0x43
#8 0xffffffff80c5e09a at vflush+0x6a
#9 0xffffffff80a45e73 at devfs_unmount+0x43
#10 0xffffffff80c55e45 at dounmount+0x515
#11 0xffffffff80c5f4d4 at vfs_unmountall+0xc4
#12 0xffffffff80c3bc05 at bufshutdown+0x2c5
#13 0xffffffff80b8bec8 at kern_reboot+0x218
#14 0xffffffff80b8bc59 at sys_reboot+0x3a9
#15 0xffffffff8105feec at amd64_syscall+0x28c
#16 0xffffffff8103c65d at fast_syscall_common+0x101
Uptime: 1m0s

The operating system has halted.
Please press any key to reboot.

BR,
Anton Haglund