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 E4FB615667D; Mon, 6 Oct 2025 23:13:43 +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=1759792424; cv=none; b=gpazi+8AyE4ZchmZyz2N9TsloKwQ/XCeUjoagNiVLw59Dt0YIjvrJpoKsbpXmbAGb87bnWiXY4eRkXFUDYvAq6kTEfTDBP4rGrx2Ag5F2UHVQvMbXQiVRlnengBjolUOdTpGqX1PfLYaLO82GWFKYD+06Oj8elYUmfNm65yN/ro= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759792424; c=relaxed/simple; bh=tLxUDT8VxXFPFnuT+CrckMnld9Zv9Ckx1PPsCInUXNw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=a8c7aeP92caA+1FKc0SjjcgNQAhBXYGL4rn8MqHkEsYCG09jCp+H2VC85QDt2nftwo4EzRMB0gdahZna0jKQx1vP1cC2G9V3zsXH9CDI3CZgas3KJ4iVSDEgnRr1qBYTegEwTAHd6q7k095e4W0LLLyviTImW1w8/UIYWAKNXTs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ANrGMgQU; 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="ANrGMgQU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4797AC4CEF5; Mon, 6 Oct 2025 23:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759792423; bh=tLxUDT8VxXFPFnuT+CrckMnld9Zv9Ckx1PPsCInUXNw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ANrGMgQUebt+vnoKrOkHX9a8pceog9ly8XuX9PtfTyjMk0YSnKnlde22xzVYIp6/v JB5y2YpQdveQSUOEb/nwuwXXKXw3DywiOGVLW9oTv3RfR/nRYbuFW1gDrzdrs+PxTD sXb0qwOD5YjT90IFApp0q8tjbnWQrtixEAlrHj8o62CdF7M7V6MIryU/QHSAE4R+WE TXQJWyhRQPOe3SHCabis8w5W7Mk3y3iFm5xDjh7O6zqp9VAlbFr1BS8cqAixQk+wjO Dz2CKHfy8gAC8+RJxz+NxSqlwu2Hr97AxJ+NBPaR8wHHyn1djSVdA42XTP8LqCMoW2 ahr2/YVOldHNw== Date: Mon, 6 Oct 2025 19:13:39 -0400 From: Sasha Levin To: Nathan Chancellor Cc: patches@lists.linux.dev, stable@vger.kernel.org, "Borislav Petkov (AMD)" , tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH AUTOSEL 6.17-5.4] x86/build: Remove cc-option from stack alignment flags Message-ID: References: <20251006181835.1919496-1-sashal@kernel.org> <20251006215505.GB3234160@ax162> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20251006215505.GB3234160@ax162> On Mon, Oct 06, 2025 at 02:55:05PM -0700, Nathan Chancellor wrote: >On Mon, Oct 06, 2025 at 02:17:33PM -0400, Sasha Levin wrote: >> From: Nathan Chancellor >> >> [ Upstream commit d87208128a3330c0eab18301ab39bdb419647730 ] >> >> '-mpreferred-stack-boundary' (the GCC option) and '-mstack-alignment' >> (the clang option) have been supported in their respective compilers for >> some time, so it is unnecessary to check for support for them via >> cc-option. '-mpreferred-stack-boundary=3' had a restriction on >> '-mno-sse' until GCC 7.1 but that is irrelevant for most of the kernel, >> which includes '-mno-sse'. >> >> Move to simple Kconfig checks to avoid querying the compiler for the >> flags that it supports. >> >> Signed-off-by: Nathan Chancellor >> Signed-off-by: Borislav Petkov (AMD) >> Link: https://lore.kernel.org/20250814-x86-min-ver-cleanups-v1-2-ff7f19457523@kernel.org >> Signed-off-by: Sasha Levin >... >> ## Backport Status: NO >... >> **Dependency Analysis:** >> - Requires minimum GCC 8.1 for x86 (introduced in v6.15 via commit >> a3e8fe814ad1) >> - Requires minimum Clang 15.0.0 for x86 (commit 7861640aac52b) >> - Both requirements are satisfied in 6.17 stable tree (verified via >> scripts/min-tool-version.sh) >> - GCC 7.1+ supports `-mpreferred-stack-boundary=3` with `-msse` (per GCC >> commit 34fac449e121) >... >> ### Conclusion >> >> While this commit is technically safe and provides a marginal build-time >> performance improvement by eliminating unnecessary runtime compiler >> checks, **it does not meet the fundamental requirement for stable kernel >> backporting**: it does not fix a bug that affects users. >> >> The commit is purely a cleanup that removes obsolete code after compiler >> minimum version requirements were raised. Such cleanups belong in >> mainline development, not stable trees, which should focus exclusively >> on fixing bugs that impact users. >> >> The fact that it was auto-selected by AUTOSEL does not override the >> documented stable kernel rules. This commit should be **rejected** from >> stable backporting or **reverted** if already applied. > >Based on all of this, I would agree that it is not really suitable for >backporting (at least not beyond 6.15, whereas the subject says back to >5.4), so why was this still sent for review? Sorry for the noise, I thought I dropped this one :( -- Thanks, Sasha