linux-kernel - Re: [PATCH v8] x86: mce: kexec: switch MCE handler for kexec/kdump

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Message-ID: <20150410072448.GA28074@pd.tnic>
Date:	Fri, 10 Apr 2015 09:24:48 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc:	"Luck, Tony" <tony.luck@...el.com>, Ingo Molnar <mingo@...nel.org>,
	Prarit Bhargava <prarit@...hat.com>,
	Vivek Goyal <vgoyal@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Junichi Nomura <j-nomura@...jp.nec.com>,
	Kiyoshi Ueda <k-ueda@...jp.nec.com>
Subject: Re: [PATCH v8] x86: mce: kexec: switch MCE handler for kexec/kdump

On Fri, Apr 10, 2015 at 04:07:26AM +0000, Naoya Horiguchi wrote:
> ... wait, changing cpu_online_mask might confuse admins who try to
> analyze the kdump, especially when the problems causing panic are CPU
> related issues?

Well, if you're offlining the CPUs before doing the dump, you're already
changing the system, aren't you? So why lie to people?

> In the similar way, changing tolerant value loses the original value,
> although this is unlikely to be a problem. But if we change it, using
> an upper bit to keep lowest 2 bit to save the original value is better?

I don't think that you need to do that - you can see from the original
kernel's dmesg whether an MCE happened - we're normally very vocal. If
the user tried to deliberately suppress that, then that's her fault
only.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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