Re: warning in arch/x86/kernel/cpu/mtrr/generic.c:400 with2.6.29-rc3 on IBM x3400

From: Ingo Molnar
Date: Wed Feb 11 2009 - 05:44:02 EST



* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > * Morten P.D. Stevens <mstevens@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> >> Hi,
> >>
> >> Update:
> >>
> >> the same issue with a linux 2.6.28.4 kernel.
> >>
> >> [ 0.000000] ------------[ cut here ]------------
> >> [ 0.000000] WARNING: at arch/x86/kernel/cpu/mtrr/generic.c:404 generic_get_mtrr+0xdf/0x119()
> >> [ 0.000000] mtrr: your BIOS has set up an incorrect mask, fixing it up.
> >
> > buggy BIOS most likely. Had the kernel not fixed up the MTRRs you'd have
> > a very slow and unhappy system now.
>
> please try:
> diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
> index 0c0a455..7a359ce 100644
> --- a/arch/x86/kernel/cpu/mtrr/generic.c
> +++ b/arch/x86/kernel/cpu/mtrr/generic.c
> @@ -397,7 +397,8 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
> tmp |= ~((1<<(hi - 1)) - 1);
>
> if (tmp != mask_lo) {
> - WARN_ONCE(1, KERN_INFO "mtrr: your BIOS has set up an incorrect mask, fixing it up.\n");
> + printk(KERN_INFO "mtrr: BIOS set mask_lo: %x should be %x, fixing it up\n", mask_lo, tmp);
> + WARN_ONCE(1, KERN_INFO "mtrr: your BIOS has set up an incorrect mask.\n");
> mask_lo = tmp;
> }
> }

Could you please embedd this info in the WARN_ONCE() itself please, so that it gets
reported as one unit? (and send a proper changelogged patch, etc.) WARN_ONCE() is a
full printk as well so you can add anything to it.

Thanks,

Ingo
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