lock order reversals w/ backtrace

A few days ago I started running 11.0-CURRENT at r260971 for the first time.

The last couple of times I shutdown my system I noticed 2 or 3 short "lock
order reversal" messages with accompanying backtraces scroll by. Do these
messages represent a problem that I should report or can I ignore them as
debug in nature? If I should report them, how or where do these messages
get logged? I can find no reference to them in syslog or anywhere else upon
my subsequent reboot.

I also had a couple of these messages pop up the other day while
mounting/umounting USB thumb drives. I did not think anything of them at
the time as the mounts/umounts completed successfully.

Please advise. Thanks.

-Tom