From: Sohil Mehta <sohil.mehta@intel.com>
To: Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
"Maciej Wieczor-Retman" <m.wieczorretman@pm.me>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
<x86@kernel.org>, <pawel.chmielewski@linux.intel.com>,
Farrah Chen <farrah.chen@intel.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>,
<stable@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 1/3] x86/cpu: Clear feature bits disabled at compile-time
Date: Thu, 12 Feb 2026 15:04:44 -0800 [thread overview]
Message-ID: <19d3f1c8-01aa-4a50-81e0-6af3fb7fe9cd@intel.com> (raw)
In-Reply-To: <A9F52EC5-EC74-43BB-BB3F-351F684BF5CE@alien8.de>
On 2/12/2026 1:51 PM, Borislav Petkov wrote:
> On February 12, 2026 9:34:31 PM UTC, "H. Peter Anvin" <hpa@zytor.com> wrote:
>> As the original author of the code I'm pretty sure that bug was always there.
>
> So, we don't need to backport it anywhere, we change it now in 7.0 or whatever and so be it. We can backport a documentation patch if someone is really pounding on it beint precisely correct for whatever reason...
>
>
Can we just deprecate the "Flags" bits of /proc/cpuinfo at this point?
No production software can be using this meaningfully. We have always
said that the *absence* of the feature doesn't mean anything. The
feature could be disabled or the kernel doesn't know about it.
And now we've realized that the *presence* of the feature in
/proc/cpuinfo doesn't mean anything either.
Should we come up with a more thought-out mechanism for user space
feature detection?
next prev parent reply other threads:[~2026-02-12 23:04 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-12 15:33 [PATCH v5 0/3] x86: Capability bits fix and required bits sanity check Maciej Wieczor-Retman
2026-02-12 15:34 ` [PATCH v5 1/3] x86/cpu: Clear feature bits disabled at compile-time Maciej Wieczor-Retman
2026-02-12 15:58 ` Borislav Petkov
2026-02-12 16:23 ` Maciej Wieczor-Retman
2026-02-12 21:34 ` H. Peter Anvin
2026-02-12 21:51 ` Borislav Petkov
2026-02-12 23:04 ` Sohil Mehta [this message]
2026-02-12 23:47 ` Borislav Petkov
2026-02-13 0:14 ` Sohil Mehta
2026-02-13 0:36 ` Sohil Mehta
2026-02-13 0:58 ` Borislav Petkov
2026-02-13 20:11 ` H. Peter Anvin
2026-02-12 15:35 ` [PATCH v5 2/3] x86/cpu: Check if feature string is non-zero Maciej Wieczor-Retman
2026-02-13 0:28 ` Sohil Mehta
2026-02-13 10:02 ` Maciej Wieczor-Retman
2026-02-13 18:22 ` Sohil Mehta
2026-02-13 19:10 ` Maciej Wieczor-Retman
2026-02-13 20:00 ` Sohil Mehta
2026-02-13 20:26 ` Maciej Wieczor-Retman
2026-02-13 20:15 ` H. Peter Anvin
2026-02-13 20:24 ` Maciej Wieczor-Retman
2026-02-12 15:35 ` [PATCH v5 3/3] x86/cpu: Required feature bits sanity check Maciej Wieczor-Retman
2026-02-13 20:17 ` H. Peter Anvin
2026-02-13 20:23 ` [PATCH v5 0/3] x86: Capability bits fix and required " H. Peter Anvin
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