Hi,
   I updated my sources the other day (after several months) and find that
union filesystem has gone haywire..  I'm not getting my backtrace copied
to dmesg, but with a LOCKDEBUG and DIAGNOSTIC kernel I see the following
very repeatably:

boot -s
NetBSD galant 4.99.9 NetBSD 4.99.9 (GALANT) #0: Sun Jan 28 22:56:06 GMT 2007  plunky@galant:/var/obj/sys/arch/i386/compile/GALANT i386
$ mount -t union -o -b /etc /mnt
$ ls /mnt
(is ok)
$ ls -l /mnt
panic: lockmgr: release of unlocked lock!
db> bt
cpu_Debugger(..
panic(..
_lockmgr(..
ufs_unlock(..
VOP_UNLOCK(..
union_mkshadow(..
union_lookup(..
VOP_LOOKUP(..
lookup(..
namei(..
sys___lstat30(..
syscall_plain(..

Is this likely to be due to a recent change?  I use a custom kernel
configuration to keep the size down but will build a GENERIC_LAPTOP and
see if there is any difference..

iain