[coLinux-users] Re: [coLinux-devel] A fix for the SIGFPE problem (>20040622)

[<sl...@bl...>]

Dan Aloni <da...@co...> writes:

> Thanks to Joe I was able to reproduce the problem locally and worked
> on a fix which makes the problem disappear.

Yay!  Thank you, thank you, thank you.

> For the technical aspect: Since until now none of the code in 
> arch/i386/kernel/head.S actually runs when coLinux starts I've suspected
> that there could be some initialization problem - if the kernel is not 
> precisely aware of the CPU's capabilities and decides not to save the 
> MMX registers between context switches it can indeed cause a problem. In 
> a multi-process scenario (such as the one with gdb and Joe's program) the 
> problem was indeed triggered before.

Here's my big question:  How could things work at all?  Was it
sometimes saving MMX registers between context switches and sometimes
not?  I saw a lot of behavior under the debugger which left me puzzled
about this.

> I've already commited the patch into the monotone server. If you can
> check that firefox / xdvi aren't crashing anymore I'd be glad.

Okay, I am downloading the 20040910 snapshot.  (Am I correct in
assuming the fix is in this snapshot?)  I hope I will have time to try
it out next week.

-- 
Joe