MCE machine check exceptions - status, tools?

Andriy Gapon avg at
Wed Jul 28 09:58:59 UTC 2010

on 28/07/2010 12:31 V. T. Mueller, Continum said the following:
> Hello,
> By searching the net I was only able to find that "better support" for
> 9.0 is on its way. So I'd like to ask if MCEs (like ECC-related messages
> from, say Supermicro boards) are being already processed by the kernel.
> Are there any (plans for) tools to handle and process these messages in
> userland?
> The amount of memory and memory modules keeps increasing, so MCE logging
> for non A-brand hardware (these trigger LEDs and/or tools from firmware)
> appears to gain increasing importance, too.
> I'd be grateful for hints, URLs, tips etc.

MCA support is in current and stable/8.
I believe that it's enabled by default, so there is not much to configure or to
do except watching for MCE reports in system log (or via hw.mca.count).
That's for correctable MCEs though, non-correctable would result in panic.

See sys/x86/x86/mca.c code for details.
John Baldwin has a tool that produces more human-friendly description of the
exceptions should you ever get one.

Andriy Gapon

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