linux-kernel - Re: [PATCH] x86/msr: add CPU_OUT_OF_SPEC taint name to "unrecognized" pr

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Message-ID: <20251102120922.GAaQdJ8noSCgyoTE2F@fat_crate.local>
Date: Sun, 2 Nov 2025 13:09:22 +0100
From: Borislav Petkov <bp@...en8.de>
To: Marc Herbert <marc.herbert@...ux.intel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/msr: add CPU_OUT_OF_SPEC taint name to
 "unrecognized" pr_warn(msg)

Hi,

On Sat, Nov 01, 2025 at 08:19:27PM -0700, Marc Herbert wrote:
> I just struggled to make sense of some unrelated crash logs and that's
> really all from my point of view. I mean all for now at least.

There's the answer to my question! :-)

>   pr_warn( "... (pid: %d), tainting CPU_OUT_OF_SPEC.\n",

Right, or simply "tainting kernel" suffices. Like other code does. So that you
can find the word "taint" in the logs and you know where it comes from. As
this is what you want.

> This patch is not "really necessary". Its purpose is only to save hours
> or even days for people trying to make sense of crash logs. In my ideal
> world, it should always be easy to tell "who tainted what when" from the
> logs without an corresponding expert and/or searching the source code.

Yap, makes sense.

> I admit this could harm job security ;-)

Yeah, although there are always other, more interesting things to hack on. :-)

So yeah, v2 with the agreed upon changes sounds good.

Thx.

-- 
Regards/Gruss,
    Boris.

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