Messages in this thread | | | From | Jürgen Mell <> | Subject | Re: CONFIG_PREEMPT causes corruption of application's FPU stack | Date | Sun, 18 May 2008 17:57:10 +0200 |
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On Sonday, 18. May 2008, you wrote: > 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?
Yes, that is correct. The error is present from the 2.6.22 SUSE kernel up to the most recent mainline kernel. It is also present in the standard SUSE kernel, if I just modify *only* CONFIG_PREEMPT. What makes me wonder: I am using the machine in a production environment for programming, multi-media etc. Why does only the Einstein program catch the SIGFPE? Normally I would expect other programs to crash, too, if the problem is present. But up to now this never happened.
> If you see it in the kernel.org kernel, can you please do a git-bisect > to see which commit caused the problem?
This is a bit of a problem. I do not know whether there was *ever* a kernel version with CONFIG_PREEMPT and without this problem as I have not tried any older kernel version yet. I will go back to SUSE 10.2 and try the 2.6.18 kernel that comes with it.
Bye, Jürgen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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