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SubjectRe: Uhhuh. NMI received for unknown reason 2c on CPU 0.
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On Thursday, January 31, 2013 02:18:05 PM Borislav Petkov wrote:
> On Thu, Jan 31, 2013 at 09:28:12AM +0100, Jiri Slaby wrote:
> > And, does it happen if you switch all of them but NMI wtd in there?
>
> No, but something else happens. Here's the whole dance:
>
> 1. Switch all tunables except "NMI watchdog should be turned off" to "Good"
> 2. suspend to disk
> 3. resume... all good
> 4. switch "NMI watchdog should be turned off" to "Good"
> 5. suspend to disk
> 6. resume... all good
> 7. start powertop, toggle "Wireless Power Saving for interface wlan0" twice.
> I.e., "Good" -> "Bad"; "Bad" -> "Good".
>
> -> Boom! Unknown reason NMI. It happened right during the toggle because
> it appeared in the framebuffer console (no X) right during me toggling
> this.
>
> So, it is something getting fishy *after* the watchdog gets disabled.
> Something remains funny and dangling, causing it to fire an NMI because
> it is an NMI watchdog (doh!)... Could it be that the watchdog_disable
> fact doesn't get communicated to the image kernel somehow, or maybe
> delayed?

The image kernel has no idea whether or not the watchdog has been disabled in
the boot kernel. It needs to be disabled in both.

>
> > And if I pass nmi_watchdog=0 to the image kernel, it should be gone I
> > guess.
>
> How do you pass options the image kernel?

The image kernel has the same set of command line options that was used by
that kernel before hibernation.

Thanks,
Rafael


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.


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