Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs

From: Ingo Molnar
Date: Wed May 04 2011 - 06:26:01 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> * Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> > But I rather suspect, that CONFIG_SLUB=y is the thing we need to look at. The
> > lockless fastpath cmpxchg comes to my mind.
>
> Hm, and CONFIG_X86_ELAN, as Linus noted, has an impact on the cmpxchg
> implementation.

Walter, could you please test the patch below on a failing kernel?

Note, the patch is actually incorrect for a real Elan box, but should work on
Walter's box - and should avoid the cmpxchg8b_emul implementation on that box.

Thanks,

Ingo

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 6a7cfdf..0783906 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -402,7 +402,7 @@ config X86_TSC

config X86_CMPXCHG64
def_bool y
- depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM
+ depends on X86_PAE || X86_64 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MATOM || X86_ELAN

# this should be set for all -march=.. options where the compiler
# generates cmov.
--
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