Re: Possible FPU context corruption w/ CONFIG_PREEMPT

From: Brian Gerst
Date: Sat Nov 27 2010 - 00:59:16 EST


On Fri, Nov 26, 2010 at 10:31 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello, guys.
>
> Heinz-Bernd Eggenstein reports a possible FPU context corruption w/
> CONFIG_PREEMPT. ÂPlease take a look at the following forum post.
>
> Âhttp://einstein.phys.uwm.edu/forum_thread.php?id=8516
>
> openSUSE 11.3 desktop kernel which has CONFIG_PREEMPT set is
> triggering SIGFPE while the default kernel w/o preemption works fine.
> He also notes that a similar bug was fixed in 2008 by commit 06c38d5e
> (x86-64: fix FPU corruption with signals and preemption) from Suresh.
> Does it ring anyone's bell?
>
> Heinz, is there a simple procedure to reproduce the problem, or would
> it be possible to lure you into bisection?
>
> Thanks.
>

This might be fixed by commit a4d4fbc7735bba6654b20f859135f9d3f8fe7f76
(Disable preemption when using TS_USEDFPU).

--
Brian Gerst
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