Re: 2.6.38-rc2: Uhhuh. NMI received for unknown reason 2d on CPU 0.

From: Ingo Molnar
Date: Wed Feb 16 2011 - 05:10:16 EST



* Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:

> On 2/16/11, Ingo Molnar <mingo@xxxxxxx> wrote:
> >
> > * Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:
> >
> >> On Wed, Feb 16, 2011 at 11:37 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
> >> ...
> >> >> >>
> >> >> >
> >> >> > Ping on this problem, still seeing
> >> >> >
> >> >> > Uhhuh. NMI received for unknown reason 3c on CPU 0.
> >> >> > Do you have a strange power saving mode enabled?
> >> >> > Dazed and confused, but trying to continue
> >> >> >
> >> >> > on my Pentium-D system here with latest Linus head.
> >> >> >
> >> >> > its sometimes 3c, sometimes 3d, I'm going to bisect and push for
> >> >> > reverts if nobody still has any clue about how to fix this.
> >> >> >
> >> >> > Dave.
> >> >> >
> >> >>
> >> >> We still trying to resolve it but without success yet. There is no
> >> >> easy way to revert it. One of the option might be to disable perf on
> >> >> p4 for a while. If this is acceptable -- i'll cook such patch and send
> >> >> it to Ingo. Hm?
> >> >
> >> > That's not really acceptable - need to fix it or revert it to the last
> >> > working
> >> > state. Which commit broke it?
> >> >
> >> > Thanks,
> >> >
> >> > Ingo
> >> >
> >>
> >> I can't say you the commit id after which unknown-nmi start happening
> >> (i'm out of git tree
> >> at moment) but even then this commit should not be reverted since the
> >> problem is in
> >> p4 code not in the rest of perf system.
> >>
> >> I have two patches here (attached) and would really appreciate of
> >> their testing on HT machine
> >> together with kgdb bootup tests enabled. Dave could you please?
> >
> > Could these patches fix Dave's non-kgdb problem? Dave isnt using kgdb but is
> > probably using perf which triggers NMIs? Dave, can you confirm that?
> >
> > And it's a spurious NMI message, not actual lockup or other misbehavior,
> > right?
> >
> > Thanks,
> >
> > Ingo
> >
>
> For nonkgdb case 'unflagged nmi fix' patch should be enough. i've
> tested it on non-ht machine by self. without it there is no lockup
> but only a message about unknown nmi.

Ok, please submit it ASAP then - that ought to address the regression. Please Cc:
Dave to the patch.

Thanks,

Ingo
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