linux-kernel - Re: [PATCHv3] x86/mce: Fix regression. All error records should report via /dev/mcelog

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Message-ID: <CA+8MBbJc8ed898L_JgHetv7EdVTo6EyMiyKv+=neUtU79=gkBw@mail.gmail.com>
Date:	Wed, 11 Feb 2015 10:11:00 -0800
From:	Tony Luck <tony.luck@...il.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	X86-ML <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux Edac Mailing List <linux-edac@...r.kernel.org>
Subject: Re: [PATCHv3] x86/mce: Fix regression. All error records should
 report via /dev/mcelog

On Mon, Feb 9, 2015 at 10:00 AM, Tony Luck <tony.luck@...el.com> wrote:
> I'm getting complaints from validation teams that have updated their
> Linux kernels from ancient versions to current. They don't see the
> error logs they expect. I tell the to unload any EDAC drivers[1], and
> things start working again.  The problem is that we short-circuit
> the logging process if any function on the decoder chain claims to
> have dealt with the problem:
>
>         ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
>         if (ret == NOTIFY_STOP)
>                 return;
>
> The logic we used when we added this code was that we did not want
> to confuse users with double reports of the same error.
>
> But it turns out users are not confused - they are upset that they
> don't see a log where their tools used to find a log.
>
> I could also get into a long description of how the consumer of this
> log does more than just decode model specific details of the error.
> It keeps counts, tracks thresholds, takes actions and runs scripts
> that can alert administrators to problems.
>
> [1] We've recently compounded the problem because the acpi_extlog
> driver also registers for this notifier and also returns NOTIFY_STOP.

So I see that this missed the x86/ras pull request to Linus.  Will you be doing
another one this merge window?  Or should I just send this direct to Linus?

-Tony
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