panic with deactivated geom mirror (both 9.2 and 10.0-RC2)

Greetings all -

I've got a completely reproducible panic when issuing a
'gmirror status' command on a recently deactivated gmirror.

NOTE:  This only happens on a machine with more than 1 CPU.

I filed a bug report on it:

http://www.freebsd.org/cgi/query-pr.cgi?pr=184985

Script to reproduce the panic:
(assumes /dev/ada0p3 is a scratch partition)

while :
do
   gmirror label -v scratch /dev/ada0p3
   newfs /dev/mirror/scratch
   mount /dev/mirror/scratch /mnt
   umount -f /mnt
   gmirror deactivate scratch /dev/ada0p3
   gmirror status scratch
done

I've attached the core.txt.0 file from the crash under 10.0-RC2.
Probably stripped by the mailing list. A copy is at
	http://www.pix.net/staff/lidl/freebsd/core.txt.0

-Kurt