From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F9E52853E2 for ; Thu, 21 Aug 2025 02:00:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755741657; cv=none; b=snb1niHbJESlgaMoLXUzAVjRLVBeysg6t3MORb/aVtHGtuxZZFGhCWg0RyjVA03UqgHJJWHouSz5ptQiRLzIFG1FUDT7t+mGBMM5+VSyZKxgW/Cu9vhkbGkiT2rAdo/pZcPfj1LTViapF+rXgqu57YRo84sBPBCGmBG/GP0XTsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755741657; c=relaxed/simple; bh=Vvso8Kr/4e0NoAO0JOi2KlOzfHJm34wV62jJixj6yPo=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=K5jsUYO3XjhcWMfrlKrO10e4swBjvWTm1mqlpjwI7p8pbjJTzRMR5LzuqIUB1nMQwrCGIFFzlff2LJTaXdpv4HEwNbtXSM77a7OLnfct10Hb5uqsaukPfACzjsDRZKzRiJu7GOYwIv0cIbMFuwF5lwwWJhO+unFNrPkhnQDmo+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dBjDFPZi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dBjDFPZi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CADE1C4CEE7; Thu, 21 Aug 2025 02:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755741657; bh=Vvso8Kr/4e0NoAO0JOi2KlOzfHJm34wV62jJixj6yPo=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=dBjDFPZieWHAeQ+r8fkKDn/Lkcl32aq30SFEOJjPr7jSRTSgaEn9oLcwIugiJDjGj Gzwj4DY21b0Zg2CjhrAvdC35UTahxAuR3KLwFCt8PR4R7+aDMKpvkB9DvGKJGuDOO1 i6nHQIFHmmzsmOA6Eb6A3DifWeKLLxsyus07+UcwrBn8x8ANJAss5tlq1e8Qgwa+D5 IGWWYxTuCRxonoBLbXudLbzpddOouUFIGfqbveeYeNn2mUvxEoM4vYLJrvmgADGjDt PrGJKxJplLqln/17ViW9eTUws3GXekdC4Z7OBM+7encqKAnr26iUmB2oFGxAGgdWMz 8Wcn63ek3SU8w== Date: Wed, 20 Aug 2025 19:00:52 -0700 From: Kees Cook To: Marcos Del Sol Vives , Borislav Petkov CC: "Ahmed S. Darwish" , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Brian Gerst , Uros Bizjak , Ard Biesheuvel , David Kaplan , "Peter Zijlstra (Intel)" , Andrew Cooper , Oleg Nesterov , "Xin Li (Intel)" , Sabyrzhan Tasbolatov Subject: Re: [PATCH] x86: add hintable NOPs emulation User-Agent: K-9 Mail for Android In-Reply-To: <3db7d599-c2a7-4bec-94b1-4872649dde8d@orca.pet> References: <20250820013452.495481-1-marcos@orca.pet> <2cd7b099-095d-405c-a7d9-b0f1f72184c2@orca.pet> <20250820094347.GDaKWY02hR3AAoT7la@fat_crate.local> <20250820095556.GEaKWbrMh24T7jTfBg@fat_crate.local> <3db7d599-c2a7-4bec-94b1-4872649dde8d@orca.pet> Message-ID: <19EDD0A4-9466-4D5F-B312-BCA293AC660E@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On August 20, 2025 3:01:30 AM PDT, Marcos Del Sol Vives wrote: >El 20/08/2025 a las 11:55, Borislav Petkov escribi=C3=B3: >> On Wed, Aug 20, 2025 at 11:51:27AM +0200, Marcos Del Sol Vives wrote: >>> I mean, they should know what they need to recompile if they want to, = not >>> just that their machine is having a bug triggered by some binary=2E >>=20 >> And what's stopping you from writing a proper error message explaining = that? >>=20 >> And issuing that error message *exactly once* instead of flooding dmesg= for no >> good reason? > >Please define "once"=2E Once per what? Per boot? Per executable? Per proc= ess? > >Once per boot would mean they'd need to reboot to see if any other execut= ables >are affected=2E Per executable AFAIK there are no facilities to do that, = and the >closest is per process which is what it's currently being done (again, li= ke >IOPL emulation which was already deemed okay a couple years ago and merge= d >into the kernel) If they want to see them again, just:=20 echo 1 >/sys/kernel/debug/clear_warn_once --=20 Kees Cook