linux-kernel - Re: [PATCH 07/14] mce3: pass mce info to EDAC for decoding

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Message-ID: <20090721110458.GB29028@basil.fritz.box>
Date:	Tue, 21 Jul 2009 13:04:58 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Borislav Petkov <borislav.petkov@....com>
Cc:	Andi Kleen <andi@...stfloor.org>, mingo@...e.hu, hpa@...or.com,
	tglx@...utronix.de, norsk5@...oo.com, aris@...hat.com,
	linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH 07/14] mce3: pass mce info to EDAC for decoding

On Tue, Jul 21, 2009 at 12:44:43PM +0200, Borislav Petkov wrote:
> On Mon, Jul 20, 2009 at 08:04:46PM +0200, Andi Kleen wrote:
> > On Mon, Jul 20, 2009 at 06:12:58PM +0200, Borislav Petkov wrote:
> > > Use a weakly defined symbol instead of ugly ifdefs.
> > 
> > I'm not sure what you're trying to archive, but if you're
> > trying to catch corrected MCs you're hooking into the 
> > wrong function. print_mce is only called for PCC=1.
> 
> Well, I was able to mce-inject a PCC=0 MCE with UC set:

Try it without UC=1. 

> 
> > Also if you're checking for specific banks you
> > need to check for vendor/cpu model first of course.
> > In your current implementation e.g. a Intel CPU
> > would pass some random event into your AMD specific code,
> > which is probably not intended and might even crash.
> 
> Actually I wanted to worry about that only after we have more than one
> vendor-specific MCE decoders :).

But your code is always unconditionally called when the code
is linked in.  I suspect i'll just crash on systems
where amd64_edac is not initialized.

> > It would be probably cleaner if you defined a standard
> > notifier chain interface.
> 
> Sounds like a cleaner solution, at a first glance. Will look into it.

Actually on second though a notifier chain is a bad idea
because there is too much risk having bad modules mess
up machine check handling. It's a critical path like
oops handling.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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