When trying to do a

 mount -t null /var/obj /usr/src

I just got a 

 panic: lockmgr: locking against myself

This was on a SS10, using a -current kernel of May 19. If there have
been made fixes in the meantime, please let me know, also if you need
more information (didn't try to crash my machine once again until now.. :-))

Cheers,
Benni