Lock order reversal errors during boot

Greetings,

My first post here so please be gentle.

I am seeing 'lock order reversal' errors during boot on 11-CURRENT - 
r298793.  A sample error:

lock order reversal:
  1st 0xfffff8011280d068 ufs (ufs) _at_ /usr/src/sys/kern/vfs_subr.c:2498
  2nd 0xfffffe01ca539400 bufwait (bufwait) _at_ 
/usr/src/sys/ufs/ffs/ffs_vnops.c:263
  3rd 0xfffff80112a23b78 ufs (ufs) _at_ /usr/src/sys/kern/vfs_subr.c:2498
stack backtrace:
#0 0xffffffff80a94bf0 at witness_debugger+0x70
#1 0xffffffff80a94ae4 at witness_checkorder+0xe54
#2 0xffffffff80a0fdd6 at __lockmgr_args+0x4d6
#3 0xffffffff80ce9626 at ffs_lock+0xa6
[...snip...]

I'm not sure if this is even something I should report, but better safe 
than sorry, yes?

I'm attaching the full dmesg for more information.

Sincerely,

Will Brokenbourgh