Re: Freeze on FPU exception with Athlon

From: adrian (jimbud@lostland.net)
Date: Sat Nov 18 2000 - 02:20:04 EST


On 17 Nov 2000, Linus Torvalds wrote:

> In article <20001118014019.18006.qmail@web3404.mail.yahoo.com>,
> =?iso-8859-1?q?Markus=20Schoder?= <markus_schoder@yahoo.de> wrote:
> >The following small program (linked against glibc 2.1.3) reliably
> >freezes my system (Athlon Thunderbird CPU) with at least kernels
> >2.4.0-test10 and 2.4.0-test11-pre5. Even the SysRq keys do not work
> >after the freeze.
> >
> >Older kernels (e.g. 2.3.40) seem to work. Any Ideas?
>
> It certainly doesn't happen for me on any of the machines I work with,
> but it wouldn't compile as-is for me, so I exchanged the FPU setting
> with a simpler
>
> asm("fldcw %0": :"m" (0));
>
> which should do the equivalent (ie unmask divide by zero errors). Does
> that make a difference for you?
>
> Can you try to figure out where it started happening? Ie try test9 and
> back too, to figure out what might be bringing it on...
>
> I sure as hell hope this isn't an Athlon issue. Can other people try
> the test-program and see if we have a pattern (ie "it happens only on
> Athlons", or "Linus is on drugs and it happens for everybody else").
>

I couldn't get it to freeze. I tried it with asm("fldcw %0": :"m" (0))
and with fesetenv() using gcc -lm to link it. I have glibc-2.1.2,
egcs 2.91.66, and 2.4.0-test10.

Regards,
Adrian

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