Re: Uhhuh. NMI received for unknown reason 2c on CPU 0.

From: Bjorn Helgaas
Date: Wed Jan 30 2013 - 12:28:10 EST


On Tue, Jan 29, 2013 at 8:42 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Tue, Jan 29, 2013 at 02:32:56PM -0700, Bjorn Helgaas wrote:
>> Konstantin has some fixes for an e1000e power management issue related
>> to suspend/resume that he observed on an x220. He didn't see an NMI,
>> and apparently his problem has been around for a long time,
>
> Yeah, this is one of those issues you don't see *every* s/r cycle and
> besides, I just got this box and haven't run 3.{6,7} on it yet (maybe
> never will :-)).
>
>> so no idea whether it could be related. I just noticed the conjunction
>> of thinkpad/e1000e/resume/power saving in both reports.
>>
>> https://lkml.org/lkml/2013/1/18/147
>
> Yes, thanks Bjorn, that was a good suggestion. Btw, from reading the
> thread, those patches still need cooking a bit more, AFAICR people's
> objections/comments. Or should I go ahead and test them?

You're right, I don't think we're quite ready to merge those patches.
But if your NMI is easy to reproduce, it might be worth removing
e1000e altogether to see if it still happens. I noticed in your
original log that the NMI occurred 5 seconds after the e1000e message,
and I could imagine some CPU or PCI response timeout being 5 seconds.

> It's just that I'm overly cautious every time I hear e1000e is involved:
>
> www.linux-magazine.com/content/download/62169/484085/file/Security_Lessons_Ftrace.pdf

Thanks for the pointer, that was an interesting read :)

Bjorn
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