5.3-BETA7 install cd: kernel trap 12 with interrupts disabled

[Robert Watson]

On Fri, 15 Oct 2004, Guido van Rooij wrote:

> It turns out this was a memory problem. Refitting the dimms was all
> that was needed to 'solve' the issue. The weird thing is that
> 1. The BIOS had memtesting enabled and did not complain
> 2. W2K seemed to install ok (though I never let it hit the disk)
> 3. FBSD would repeatedly crash at exactly the same spot.
> 
> I am beginning to wonder if we should have a boot option that enables a
> thorough memtest from within the kernel...(e.g. boot -m). 

I guess the old /dev/test_for_shoddy_workmanship driver is working :-).

It's probably just bad luck -- BIOS memory testing is generally pretty
poor, and it could just be FreeBSD stored your root vnode pointer (or some
other critical thing) in a memory word that Win2K was using for an icon,
so a single bit twiddle did pretty different things.  Glad it's fixed.  I
occasionally wonder if we shouldn't build a memory tester into the FreeBSD
boot loader to help diagnose this sort of stuff, though.  Not to run every
boot, but as a diagnostics option.

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Principal Research Scientist, McAfee Research