linux-kernel - Re: [PATCH v3] x86: Clear feature bits disabled at compile-time

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Message-ID: <20250724142452.GAaIJCNFO9tLS_ezVV@renoirsky.local>
Date: Thu, 24 Jul 2025 16:24:52 +0200
From: Borislav Petkov <bp@...en8.de>
To: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Kyung Min Park <kyung.min.park@...el.com>,
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
	Tony Luck <tony.luck@...el.com>, xin3.li@...el.com,
	Farrah Chen <farrah.chen@...el.com>, stable@...r.kernel.org,
	Borislav Petkov <bp@...e.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] x86: Clear feature bits disabled at compile-time

On Thu, Jul 24, 2025 at 12:59:47PM +0200, Maciej Wieczor-Retman wrote:
> As I wrote in the v2 thread, based on what's in the documentation added at the
> commit I pointed out, the behavior is a bug.

That's all missing the whole idea of Fixes: tags and backports.

Your patch must point to the correct faulty commit which causes this
behavior or to none, which means backport everywhere. And I already
explained this to you.

Pointing to a commit documenting this doesn't make the tree *before*
that all of a sudden not affected.

What I would do is, I'd go through all stable trees and check whether
they're affected. If they are, you craft backports for all of them. You
were already asking Greg what to do.

But pointing to some innocuous commit and deciding that that is the
culprit is not what you should do.

Thx.

-- 
Regards/Gruss,
    Boris.

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