This is a NetBSD/vax 1.6ZG install running in single user mode on my
VAXstation 3100/m76.  So far, I've found that a handful of utils can
panic the system (e.g. fsck and disklabel) when trying to access the
SCSI HDs of the system.

I then attempt to make a crash dump of the system, with the intention
of pulling it up in gdb.  This doesn't seem to be working too well.

  # disklabel -r sd0
  panic: lockmgr: no context
  Stopped at      netbsd:lockmgr+0x66:    movab   lwp0, r2
  db> sync
  syncing disks... Trap: type 2, code 0, pc 8000047f, psl 4080000
  panic: trap
  Stopped at      netbsd:trap+0x177:      pushab
  scsipi_nsyncparams+0x8de7
  db> sync

  dumping to dev 20,9 offset 133572
  dump succeeded

  ?06 HLT INST
      PC = 80151F20
  >>>

When I boot the system back up at this point and run savecore, all I get
is "savecore: no core dump".  I'd hoped to use gdb on the crash dump as
looking around inside of ddb itself on the panicked system is a bit
precarious.  I'm finding that some of the debugger commands cause the
system to restart or drop unexpectedly to the console prompt.

Further suggestions would be welcomed.

-brian.