linux-kernel - Re: [PATCH] [22/28] x86: MCE: Default to panic timeout for machine checks

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Date:	Fri, 17 Apr 2009 15:12:14 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Cc:	Andi Kleen <andi@...stfloor.org>, hpa@...or.com,
	linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de
Subject: Re: [PATCH] [22/28] x86: MCE: Default to panic timeout for machine checks

On Fri, Apr 17, 2009 at 08:24:16PM +0900, Hidetoshi Seto wrote:
> Andi Kleen wrote:
> > Fatal machine checks can be logged to disk after boot, but only if
> > the system did a warm reboot. That's unfortunately difficult with the
> > default panic behaviour, which waits forever and the admin has to
> > press the power button because modern systems usually miss a reset button.
> > This clears the machine checks in the registers and make
> > it impossible to log them.
> > 
> > This patch changes the default for machine check panic to always
> > reboot after 30s. Then the mce can be successfully logged after
> > reboot.
> 
> In case if user already set panic_timeout to 5s, the that user need to
> wait extra 25s for machine check panic... ?

That's true. I'll fix that.

> 
> The idea is good, but I think some switch like "no_reboot_on_mce" would
> be required.

mce=nobootlog should do that.
If someone feels strongly I can add a separate switch.

-Andi

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