ddb: fatal breakpoint trap in supervisor mode

[SAITOH Masanobu <msaitoh%execsw.org@localhost>]

 I've noticed that NetBSD/i386 -current's ddb has a bug.

> # sysctl -w ddb.fromconsole=1
> ddb.fromconsole: 0 -> 1
(send BREAK)
> # fatal breakpoint trap in supervisor mode <============
> trap type 1 code 0 eip c02698a4 cs 8 eflags 202 cr2 bbb62da0 ilevel 8 esp 
> da980f6c
> curlwp 0xc327ed20 pid 0 lid 2 lowest kstack 0xdaad4000
> Stopped in pid 0.2 (system) at  netbsd:breakpoint+0x4:  popl    %ebp
> db{0}> c

Is this trap intended? One of my machine is recoverable from db> prompt by 'c' 
and
another is not (with "spl not lowered...).

The difference is:

 recoverable:
        serial console

 unrecoverable:
        USB keyboard

        When entering DDB, "kenel: supervisor trap page fault, code=0" is 
printed.

        When exitting by 'c', "panic: SPL NOT LOWERED ON SYSCALL EXIT" is 
printed.

I have more than 3 NetBSD/i386 machines but I tested only two machines. Sorry.

-- 
-----------------------------------------------
                SAITOH Masanobu (msaitoh%execsw.org@localhost
                                 msaitoh%netbsd.org@localhost)