Subject: MMU fault trap
To: None <port-hp300@NetBSD.ORG>
From: Nathan Gelbard <gelbard@ENGR.ORST.EDU>
List: port-hp300
Date: 02/15/1998 20:35:14
I am playing with the small change to the scsi driver to allow
Quantum drives to work. Upon boot, I still got the same message
(oscsi0 timed out after 1000 tries) x 3. Oh well.

I reverted to the kernel with the untouched scsi driver and
proceded to mount the Quantum on /mnt, and some other disk
onto /nfs. I then did a copy from nfs to /mnt. It worked
for a while, then just stopped. The flashy lights on the front
panel (hp400) still blink, and it still pings (but no telnet).
Braindeath.

So, dump to debugger, trace and:

_Debugger(c8581,c856e, 158f2c,1e46,0) + 6
_nmihand(0,0,0,2004,0) + 32
_lev7intr(?)
_mi_switch(0,0,152500,14b000,a0300004) + 12
_tsleep(f6078,4,a01a6,0) + 178
_scheduler(2017600,17fe0,c,ff002000,fffffffc) + 66
trap: bad kernel read access at 0xfb
trap type 8, code = 0x525, v = 0xfb
kernel program counter = 0xcbf4a
kernel: MMU fault trap
Caught exception in ddb.
_main() + 502
_main() + 502

Now, maybe that was all to me hitting the debugger keys (shit-break),
but what nags is this. Once in a while, when booting the kernel,
very near the 'parity' line (like 4th or 5th message at boot), it
freaks with a MMU fault trap, dumps a lot of hex on the screen, and
reboots. Then it wont happen for a days, then it will do it again.

This has happened on all of my  hp300/400 hardware.

Thoughts?
	
	Nate