Re: [PATCH -next] x86/mm/pat: silence a data race in cpa_4k_install

[Borislav Petkov]

On Tue, Jan 21, 2020 at 04:36:49PM +0100, Marco Elver wrote:
> Isn't the intent "x86/mm/pat: Mark intentional data race" ?  The fact
> that KCSAN no longer shows the warning is a side-effect.  At least
> that's how I see it.

Perhaps because you've been dealing with KCSAN for so long. :-)

The main angle here, IMO, is that this "fix" is being done solely for
KCSAN. Or is there another reason to "fix" intentional data races? At
least I don't see one. And the text says

"This will generate a lot of noise on a debug kernel with
debug_pagealloc with KCSAN enabled which could render the system
unusable."

So yes, I think it should say something about making KCSAN happy.

Oh, and while at it I'd prefer it if it did the __no_kcsan function
annotation instead of the data_race() thing.

Thx.

-- 
Regards/Gruss,
    Boris.

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