Re: 4.01 panic/lock issues?

[Bolo <bolo%cs.wisc.edu@localhost>]

> > Model: sun3 60
> > fpu: mc68882
> > 
> > This may be part of the problem. It appears that at some point in the
> > past life of this box, someone did the 68882 mod on it. I never caught
> > this before since it was never a problem on past SunOS or NetBSD
> > versions, but something here may be triggering it.
> 
> According to the Sun3 Archive page:
> http://www.sun3arc.org/hardpatches/3.60-tuning/fpu.phtml
> 68882 is software compatible with 68881 (except CPI),
> so I wonder if it could cause FPU related errors.
> Actually I used 68882 on 3/60 about 13 years ago (with 1.1 or 1.2?)
> and it worked fine with X11 etc.

Off the top of my head...

The size of the floating point save context can be different.
If the kernel was only compiled with code for the 68881 floating point
save size, a larger 68882 context could overflow into something else.

It won't matter for executables that don't use floating point, because
of the only-save-if-used fp code.

> Hmm, does only the mutt binary cause the problem?

Mutt probably does some floating point arith for, which
makes a save-context be generated on context switch, and boom,
something dies.

To try and reproduce it just have something that does a floating
point op, and context switches -- ato[df] or printf("%f") might be
enough to trigger it.

Bolo -- Josef T. Burger