I just caused a panic reproducibly by using gdb on a little
test program. Set a breakpoint into a signal handler and
run. The panic happened in uvm_map_lookup_entry where
map->hint is dereferenced. "hint" was 0 at that point.

That was with a kernel compiled w/o DIAGNOSTIC/DEBUG. Now
I added these options. The program doesn't panic the box
on startup anymore, but the test program under gdb doesn't
get signals at all, not even -9. After sending a signal,
the program is stuck in "vmmapbsy".

That's with today's -current on i386.

best regards
Matthias