Re: CONFIG_PREEMPT causes corruption of application's FPU stack

[Steven Rostedt <rostedt@goodmis.org>]

On Sat, May 17, 2008 at 06:31:08PM +0200, J?rgen Mell wrote:
> 
> I tracked this down to a single kernel configuration option. If 
> CONFIG_PREEMPT is set to 'y' the application will start crashing. If 
> CONFIG_PREEMPT is replaced by CONFIG_PREEMPT_VOLUNTARY, the application 
> will run without errors.
> 
> The problem is reproducible in so far as the error always occurs when 
> CONFIG_PREEMPT is set, but the time to the first occurrence varies greatly 
> from some minutes up to more than 10 CPU hours.
> 
> I found this error first on an openSUSE kernel 2.6.22.17-0.1-rt. I verified 
> the problem on the following kernel versions:
> 
> openSUSE 2.6.22.17-0.1-default
> openSUSE 2.6.23.17-ccj64-rt
> kernel.org 2.6.26-rc1
> kernel.org 2.6.26-rc2-git5

So you see this error in both the SuSE RT kernel, *and* mainline
kernel.org?

If you see it in the kernel.org kernel, can you please do a git-bisect
to see which commit caused the problem?

Thanks,

-- Steve

> 
> My CPU is an Intel Core2Duo 6420, running two of the Einstein applications 
> in 32-bit mode. From a discussion on the Einstein message boards I know 
> that other user of the application are also affected.
>