assertion: ncp->nc_refs > 0 in cache_drop

[qhwt@xxxxxxxxxxxxx]

Hello.
I got this assertion with kernel/world as of last Sunday.
It's been up about 10 hours or so before shutting down and then
panicked.
The last operation before the shutdown was building and installing
XFree86(from CVS). Its /tmp and /usr/obj are nullfs-mount of /var/tmp
and /var/obj, respectively. Traceback looks to me like it was trying
to umount /tmp when it panicked.

Regards.

Attachment: cache_drop.gz
Description: application/gunzip