linux-kernel - Re: [PATCH 2/2] x86 mce: use new printk recursion disabling interface

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Message-ID: <1338424236.14538.216.camel@ymzhang.sh.intel.com>
Date:	Thu, 31 May 2012 08:30:36 +0800
From:	Yanmin Zhang <yanmin_zhang@...ux.intel.com>
To:	Borislav Petkov <bp@...en8.de>
Cc:	ShuoX Liu <shuox.liu@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>, andi@...stfloor.org,
	Tony Luck <tony.luck@...el.com>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH 2/2] x86 mce: use new printk recursion disabling
 interface

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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