Our news server recently paniced on a mi_switch() call.  I was in the
middle of halting the machine, actually (had just entered the halt
command).

Here's the traceback:

[snip]
52 root (news1)[/var/crash]-->gdb -k netbsd.6 netbsd.6.core
GDB is free software and you are welcome to distribute copies of it
 under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.11 (i386-netbsd), Copyright 1993 Free Software Foundation, Inc...
(no debugging symbols found)...
panic: trap
#0  0xf81110a1 in mi_switch ()
(kgdb) where
#0  0xf81110a1 in mi_switch ()
#1  0xf8110ba1 in tsleep ()
#2  0xf8179fd7 in lock_clear_recursive ()
#3  0xf8179afd in lock_clear_recursive ()
#4  0xf8180612 in vm_pager_get_pages ()
#5  0xf8180678 in vm_pager_get ()
#6  0xf817a60a in vm_fault ()
#7  0xf817acdd in vm_fault_wire ()
#8  0xf817c9f8 in vm_map_pageable ()
#9  0xf817b1f3 in swapin ()
#10 0xf817b2d1 in scheduler ()
#11 0xf8107dce in main ()
(kgdb) quit
[snip]

If someone wants the core, you're welcome to it (but beware, it is
96MB)..

Thanks.

Alec

-- 
+------------------------------------+--------------------------------------+
|Alec Peterson - chuckie@panix.com   | Panix Public Access UNIX and Internet|
|Network Administrator               | New York City, NY                    |
+------------------------------------+--------------------------------------+