Paul Kranenburg writes:
> > Has anyone seen behavior in -current that processes seem to get random
> > signals (especially 26 (virtual timer alarm), and occasionally SEGV's)?
> > This is particularly noticeable after they've done a bunch of work (i.e.
> > compiling, running X).
> 
> Yes, I got bitten last week.
> 
> It turns out that process 0 overflows its stack during auto-configuration.
> The layout in locore allows for this to happen, but meanwhile a whole
> bunch of values in proc0's user structure are now filled with randomness,
> including, e.g., p_timer[IMTER_VIRTUAL], which is then propagated to all
> processes.
> 
> I think it's sufficient to re-init proc0's user structure to zero in
> machdep's cpu_startup() after all auto-configuration is done.

Wouldn't it be superior to detect and prevent the stack overflow? This
could happen on other architectures at some point, and the overflow
might go past the user structure...

Perry