Re: [tip:x86/urgent] x86/mce: Fix CMCI preemption bugs

From: Borislav Petkov
Date: Thu Apr 17 2014 - 11:26:31 EST


On Thu, Apr 17, 2014 at 02:03:34PM +0000, Luck, Tony wrote:
> > Hohum, __raw_spin_lock_irqsave does preempt_disable(). And
> > machine_check_poll should be running in irq context so why would the
> > original issue happen?
> >
> >> kernel: [ 7.341085] BUG: using __this_cpu_write() in preemptible [00000000] code: modprobe/546
> >
> > Unfortunately, I have only one line in a mail CCed to me.
> >
> > Color me confused.
>
> Is this just the missing put_cpu() that Chen Gong already sent a patch for?

I'm not sure. There's some bug report floating around which contains the
"BUG" line above but I can't seem to find/get it.

I'll boot latest Linus tree on my SNB machine to check whether it
triggers here. Ingo says CONFIG_DEBUG_PREEMPT=y is causing it but this
is all hearsay stuff from where I'm standing...

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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