Message-ID: <1338424236.14538.216.camel@ymzhang.sh.intel.com>
Subject: Re: [PATCH 2/2] x86 mce: use new printk recursion disabling
 interface
From: Yanmin Zhang <yanmin_zhang@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: ShuoX Liu <shuox.liu@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>, andi@firstfloor.org,
        Tony Luck <tony.luck@intel.com>, Ingo Molnar <mingo@elte.hu>
Date: Thu, 31 May 2012 08:30:36 +0800
In-Reply-To: <20120530090844.GA23663@liondog.tnic>
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On Wed, 2012-05-30 at 11:08 +0200, Borislav Petkov wrote:
> On Mon, May 28, 2012 at 10:07:59AM +0800, ShuoX Liu wrote:
> > Boris,
> > I checked code and found some other functions in do_machine_check() also
> > would printk something. Such as add_taint(). So i think we'd better
> > place the recursion check at the beginning and the end of
> > do_machine_check(). Also more printks later(maybe) added will benefit
> > from this. Do you agree?
> 
> I'm not sure we want to disable printk recursion for add_taint() - it
> doesn't spit out any useful information wrt MCE so we could ignore it.
add_taint might be not a good case here. We could move the recursion check
flag setting around mce_panic.


> 
> Btw, I forgot to ask: this printk recursion disabling, do you have a
> real usecase where you don't get the MCE info in dmesg and with your
> patch it works or is this purely hypothetical?
We hit it when running a MTBF testing on a Android atom mobile.

Thanks,
Yanmin


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