linux-kernel - Re: nmi_watchdog=2 regression in 2.6.21

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Message-ID: <20070830210555.GA6635@frankl.hpl.hp.com>
Date:	Thu, 30 Aug 2007 14:05:55 -0700
From:	Stephane Eranian <eranian@....hp.com>
To:	Daniel Walker <dwalker@...sta.com>
Cc:	B.Steinbrink@....de, ak@...e.de, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org
Subject: Re: nmi_watchdog=2 regression in 2.6.21

Daniel,

On Wed, Aug 29, 2007 at 06:21:59PM -0700, Daniel Walker wrote:
> On Wed, 2007-08-29 at 14:24 -0700, Stephane Eranian wrote:
> 
> 
> > Now on Core Duo, there is no PEBS anyway, so it is okay to use counter 0
> > for NMI. The problem is that the detection code in perfctr-watchdog.c
> > treats a Core Duo and a Core 2 Duo the same way as they both have the
> > X86_FEATURE_ARCH_PERFMON bit set.
> > 
> > I have attached a patch with handle the case of the Core Duo. Unfortunately,
> > I do not own one so I cannot test it. I would appreciate if you could
> > try re-applying my counter 0 -> 1 patch + this new one to see if you
> > have the problem with the NMI getting stuck.
> 
> I tested your patch .. The system doesn't hang, but the NMI seems to
> disappear .. The check_nmi_watchdog() is not called, and the NMI never
> actually starts firing .. Is that what you had intended?
> 
Yes, I realized I missed a small detail in the switch statement.
Could you try the new version?

Thanks.

-- 
-Stephane

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