Re: [PATCH] x86/mce/dev-mcelog: Call mce_register_decode_chain() much earlier

[Borislav Petkov]

On Fri, Aug 20, 2021 at 07:43:14AM -0700, Luck, Tony wrote:
> How can the kernel tell that all consumers have registered? Is there
> some new kernel crystal ball functionality that can predict that an
> EDAC driver module is going to be loaded at some point in the future
> when user space is up and running :-)

The crystal ball is called mcheck_late_init(). There's even:

        /*
         * Flush out everything that has been logged during early boot, now that
         * everything has been initialized (workqueues, decoders, ...).
         */
        mce_schedule_work();

in there. That thing is late_initcall() and by that time mcelog should
have been registered. And I wonder why isn't that working as expected...

> I think the best we could do would be to set a timer for some point
> far enough out (one minute?, two minutes?) to give a chance for
> modules to load.

Forget modules - only the built-in stuff. We cannot be waiting
indefinitely until someone loads mcelog for decoding.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette