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SubjectRe: [PATCH] x86/mce: drop cpu_missing since we have more capable mce_missing_cpus
On Tue, Nov 09, 2021 at 04:31:23PM +0800, Zhaolong Zhang wrote:
> If there is a non-recoverable mce as well, just let it print that
> reason. No need to bring the timeout message indeed. Because since
> the tolerant was set to a high level to ignore the timeout, we can
> eventually ignore them.

Here's how I see it:

/*
* Tolerant levels:
* 0: always panic on uncorrected errors, log corrected errors
* 1: panic or SIGBUS on uncorrected errors, log corrected errors
* 2: SIGBUS or log uncorrected errors (if possible), log corr. errors
* 3: never panic or SIGBUS, log all errors (for testing only)
*/

So on normal deployments, no one should fiddle with tolerant levels - so
you'll be running at tolerance level 0 by default and all should print
out. Same for level 1.

Levels 2 and 3 are, to me at least, purely for testing *only*. And,
actually, that error message should be issued regardless of the
tolerance level - only the panicking should be controlled by that. IOW,
that code should do:

if ((s64)*t < SPINUNIT) {
if (cpumask_and(&mce_missing_cpus, cpu_online_mask, &mce_missing_cpus))
pr_emerg("CPUs not responding to MCE broadcast (may include false positives): %*pbl\n",
cpumask_pr_args(&mce_missing_cpus));
if (mca_cfg.tolerant <= 1)
mce_panic(msg, NULL, NULL);
return 1;
}

because, regardless of tolerance level, saying that some cores didn't
respond is important info.

You could do that as a separate patch, on top, if you feel like it.

> I am not sure whether it should be authored by you or suggested by
> you.

Suggested is fine.

> Anyway, I will post a new patch exactly as you suggested. Please pick
> it or ignore it as appropriate :)

Thx.

--
Regards/Gruss,
Boris.

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

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