linux-kernel - Re: AMD EPYC 25 (19h): Hardware Error: Machine Check: 0 Bank 17: d42040000000011b

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Date:   Fri, 14 Apr 2023 09:46:46 -0400
From:   Yazen Ghannam <yazen.ghannam@....com>
To:     Borislav Petkov <bp@...en8.de>, Paul Menzel <pmenzel@...gen.mpg.de>
Cc:     yazen.ghannam@....com, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: AMD EPYC 25 (19h): Hardware Error: Machine Check: 0 Bank 17:
 d42040000000011b

On 4/14/23 06:24, Borislav Petkov wrote:
> On Fri, Apr 14, 2023 at 11:26:27AM +0200, Paul Menzel wrote:
>> It says “no action required”,
> 
> Yes, it means you had a single bit flip in some DIMM and it got
> corrected by the ECC so you don't need to do anything.
> 
>> but out of the identical 14 servers with the same workload this is the
>> only one having shown this errors three times.
> 
> Or you could enable CONFIG_RAS_CEC and don't see those errors anymore.
> 
> It all depends: a DIMM could be producing correctable errors for a long
> time before going bad. If ever. If you don't want to risk whatever
> you're running on that machine by a DIMM *potentially* going bad, sure,
> you can replace it. That's a budget call. :)
> 
>> Maybe the DIMM at bank 17 should just be replaced.
> 
> Bank 17 is the CPU MCA bank which reports the error - not a DIMM bank.
> In order to pinpoint the location, you should have amd64_edac loaded so
> that it decodes to which DIMM. You could try loading that module and
> injecting all errors you have to see what it says, it should work this
> way too as the error signature has everything needed for decoding,
> AFAICT.
> 
> But Yazen can chime in here if I'm off.
> 

Yes, that's right with one caveat. The info from EDAC will show the
channel/DIMM from the SoC/CPU's perspective. This may not match what is
printed on the motherboard. The board vendor will need to provide that
information.

Thanks,
Yazen