linux-kernel - RE: [PATCH] x86/mce: Always save severity in machine_check

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Date:   Mon, 12 Jun 2017 18:55:17 +0000
From:   "Ghannam, Yazen" <Yazen.Ghannam@....com>
To:     "Luck, Tony" <tony.luck@...el.com>
CC:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        Borislav Petkov <bp@...e.de>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] x86/mce: Always save severity in machine_check_poll

> -----Original Message-----
> From: linux-edac-owner@...r.kernel.org [mailto:linux-edac-
> owner@...r.kernel.org] On Behalf Of Luck, Tony
> Sent: Monday, June 12, 2017 2:08 PM
> To: Ghannam, Yazen <Yazen.Ghannam@....com>
> Cc: linux-edac@...r.kernel.org; Borislav Petkov <bp@...e.de>;
> x86@...nel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH] x86/mce: Always save severity in machine_check_poll
> 
> On Mon, Jun 12, 2017 at 11:54:06AM -0500, Yazen Ghannam wrote:
> > -		severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
> > -
> > -		if (severity == MCE_DEFERRED_SEVERITY &&
> mce_is_memory_error(&m))
> > -			if (m.status & MCI_STATUS_ADDRV)
> > -				m.severity = severity;
> > +		m.severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
> 
> So that isn't quite the same. Before we only set m.severity for memory errors
> where we had a valid address. Now you unconditionally set it.
> 
> Maybe that's more useful. But it now needs an audit of the code the
> registered notifiers to make sure they didn't assume that severity set meant
> that this is a memory error.
> 

Only the SRAO notifier checks for severity as far as I can tell, and it specifically
checks for m.serverity=MCE_SRAO_SEVERITY.

However, it looks like all the other actionable notifiers check for a memory
error either using mce_is_memory_error() or by checking the status bits
directly.

Thanks,
Yazen