> Date: Thu, 20 Nov 1997 12:39:11 -0500 (EST)
> From: woods@most.weird.com (Greg A. Woods)
> 
[ Latest pmap.c (1.88) kernel ]
> 
> Nope, it does not work here.  The GENERIC kernel has a slightly
> different behaviour -- it freezes after trying to start xterms (xclock
> appears) [well the mouse cursor and keyboard caps lock freeze].  When I
> reboot from the DDB I then get:
> 
> 	db>reboot
> 	syncing disks... done
> 	trap type=0x8, code=0x145, v=0xa8
> 	kernel: MMU fault trap
> 	Caught exception in ddb.
> 	db>
> 
> A second reboot then successfully calls the EPROM. 
> 
> Note this is on a diskless 3/60 (well a CD-ROM), 12MB RAM, and using the
> bwtwo frame buffer.  I'm booting from the NetBSD server where I built
> the kernel.
> 
> Gordon, even though your machines are headless, you should be able to
> start the X server on them as most should have at least bwtwo, no?

Oh, I just have to find table space and move one of those big HEAVY
monitors close to the machine...

> Now that it's had time to reboot let's see if it freezes the same way
> and maybe I can copy the trace from the other screen too...

You know, you can use the serial console and still run a getty on
the keyboard/display (or better, an xdm on /dev/kd).  It's a lot
easier to work on the serial console for debugging, expecially if
the "terminal" is an xterm (with logging) on another machine that
runs tip or something similar.  You can cut and past stuff into
and out of the remote console xterm.  That's how I do it.

> I don't remember if it was the same syscall(6f) as before or not, but
> I'm pretty sure it was....
> 
> In any case it seems essentially repeatable....

I'll try to find time to reproduce this here.

> The 3/260 server is still running the 11/17 (pre pmap-88.c) kernel at
> nearly 24 hours, and has done all the boot serving, kernel building,
> etc. without any problems.

OK, so maybe it is NFS-root or X related.

BTW, does the problem machine have swap space?
(i.e. what does "swapctl -l" show you?)