Re: [PATCH v8 1/3] x86/cpu: Clear feature bits disabled at compile-time

[Maciej Wieczor-Retman]

On 2026-03-02 at 21:25:04 +0100, Borislav Petkov wrote:
>On Mon, Mar 02, 2026 at 07:48:41PM +0000, Maciej Wieczor-Retman wrote:
>> The documentation from at least 5.10 onwards promises to have flags in cpuinfo
>> only if they're truly compiled and enabled. So I thought that incosistency can
>> be corrected from that point on. For the 6.18 stable kernel this particular
>> patch applies cleanly because it already started using the awk script. For the
>> older ones I took Greg's advice and prepared separate patch that worked before
>> the awk script was introduced.
>
>I don't think you got my question, lemme try again: 
>
>How serious is this bug so that you want to backport it to stable?
>
>So what if some flags appear in /proc/cpuinfo even if they're not compiled in?
>
>Is the cat going to catch fire or no one cares...?
>
>IOW, does it really need to go to stable and if so, what's the grave bug it is
>fixing?

I don't think it's some big threat. But then would you agree it'd be a good idea
to backport a change to the documentation that the cpuinfo isn't as reliable as
the documentation entry says it is? I would imagine the documentation should be
kept as accurate as possible.

-- 
Kind regards
Maciej Wieczór-Retman