linux-kernel - RE: [PATCH v3 1/2] x86, mce, severity: extend the the mce_severity mechanism to handle UCNA/DEFERRED error

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Date:	Mon, 10 Nov 2014 23:32:12 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Borislav Petkov <bp@...en8.de>,
	Aravind Gopalakrishnan <aravind.gopalakrishnan@....com>
CC:	Chen Yucong <slaoub@...il.com>,
	"ak@...ux.intel.com" <ak@...ux.intel.com>,
	"linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v3 1/2] x86, mce, severity: extend the the mce_severity
 mechanism to handle UCNA/DEFERRED error

But then I tested it ...

I injected a UC error to memory - then did a simple byte write to the target line.
This resulted in two banks logging errors:

[  124.638045] poll: CPU54 saw ec00000000010092 in bank 7
[  124.639006] poll: severity = 0
[  124.647333] poll: CPU54 saw b800000000200179 in bank 3
[  124.648322] poll: severity = 1

The bank 7 error reported as severity 0 because EN=0 ... so we took no action for it.

The bank 3 error got past that hurdle, then through the next BIT(8) set indicates a
cache error. Fell at the last check because ADDRV=0.

I think the severity table entry for the "EN" check should have been skipped
when calling from the CMCI handler. Then we would have seen severity=1
from the bank 7 error.  It would have passed the other tests too (BIT(7) and
ADDRV).

-Tony