This looks like a MI problem, though I'm really not sure.

The machine in question is a news server, NetBSD 1.3I, i386, source
probably grabbed around Jan 25.  The spool is on a ccd across a 6G IDE
disk and 2 1G SCSI disks.  It's been panicking on an irregular basis
for a while now, and this is the first time I've managed to get the
people who watch it to actually write down a stack trace.  I'm pretty
sure the process in question in expire:

kernel: page fault trap, code = 0
Stopped in expire at _extent_free+0x145: movl %es:, 0x4 (%eax)

_extent_free
_uvm_swap_free
_uvm_anfree
_amap_wipeout
_amap_unref
_uvm_unmap_detach
_uvm_unmap
_uvm_deallocate
_exitl
_sys_exit
_syscall

Is there something more I can do to debug this, assuming it happens
again?

Chris

-- 
-----------------------------------------------------cjones@math.montana.edu
Chris Jones                                          cjones@honors.montana.edu
           Mad scientist at large                    cjones@nervana.montana.edu
"Is this going to be a stand-up programming session, sir, or another bug hunt?"