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 C29F3EEC0; Thu, 9 Oct 2025 17:41:25 +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=1760031686; cv=none; b=a0daEExQ5uVBqdLeU/WLUWX3IqIqBRX3I0wpWHaH56S5hozVmk7CZfliS297w84IddD5M9ScAjnWdOIsyTXrWuxb83+Vvh0af+YbsoCSytilcm+A4X6hmkJsTJo/jHYJgEl68KQAPuUszXqAo+CoqChnaw72FkLCNJ5dQx7whKw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760031686; c=relaxed/simple; bh=K23L2usRO9cloxuukdxyKgJDZionsYzMB3U1+Yzhy30=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IGJlLnOXYw3yuOTCum9q4Z/2/ugL21l/zbwcEElnvmH8wrei8ZbmpjcSbT5JFL96rVgFRFN45I1eSvHGKMgztDt4IsJY0r3/dajPPGLjlx5U4IZPkE75AawHmyQvr9qGyCEIj3CsY6srgzUWfzYpwemWFL7q5c08S5e0GaIZLc8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ilPXDzl9; 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="ilPXDzl9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1576BC4CEE7; Thu, 9 Oct 2025 17:41:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760031685; bh=K23L2usRO9cloxuukdxyKgJDZionsYzMB3U1+Yzhy30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ilPXDzl9inaHuOpMWGvhmY+g5lALkpQvwcS3EjjxZ8qbRtZjibA2BuwnUYE4GTGWa ROSh9/863YI2HCxPdSb52bI7mFhiDEPjJETfUukumlDjwYHLTOvHaDRC/9UV30ltBr llNtSakZhlnZEChmqSyZYQYBL22Ce8AOvYL9D2rOFi4ZhGv7T2VwGF7b0XozMGPvpY Uq4Ovdr2/AfpKVCHPsb5qTsmWtOLBBKozxI7iWFqvbXq5C3urjWJM6H+5HnW8QcAaT mR42c7qiIOy3JEZZ8PwfTTGuSZXa8l3WzI6gsaZ1vnd5p5WKcEyTWLHLJ9C7E6mOCG PzP5eylm3STIA== Date: Thu, 9 Oct 2025 10:41:20 -0700 From: Nathan Chancellor To: Askar Safin Cc: linux-kbuild@vger.kernel.org, Masahiro Yamada , regressions@lists.linux.dev, linux-kernel@vger.kernel.org, miguel.ojeda.sandonis@gmail.com, nsc@kernel.org, ojeda@kernel.org, sam@gentoo.org, thomas.weissschuh@linutronix.de, Daniel Xu Subject: Re: [REGRESSION][BISECTED] kbuild: CFLAGS=-w no longer works Message-ID: <20251009174120.GA442207@ax162> References: <20251009075149.1083040-1-safinaskar@gmail.com> 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=us-ascii Content-Disposition: inline In-Reply-To: <20251009075149.1083040-1-safinaskar@gmail.com> Hi Askar, On Thu, Oct 09, 2025 at 10:51:49AM +0300, Askar Safin wrote: > #regzbot introduced: d1d0963121769d8d16150b913fe886e48efefa51 > > As well as I understand, if you want to disable warnings, you > should pass "CFLAGS=-w" to "make". Starting with d1d096312176, > this no longer works. > > Steps to reproduce: > > $ cd linux > $ git clean -f -q -d -x # To clean everything not controlled by git > $ echo 'CONFIG_64BIT=y' > /tmp/minimini > $ make allnoconfig KCONFIG_ALLCONFIG=/tmp/minimini > $ make -j32 CFLAGS=-w As Nicolas pointed out, CFLAGS has not be hooked into Kbuild for a long time, see commit 69ee0b352242 ("kbuild: do not pick up CFLAGS from the environment"). You would need to use KCFLAGS=-w to accomplish the same thing. KCFLAGS is only for the kernel build though, you would need HOSTCFLAGS=-w as well to ignore warnings when building the host programs such as objtool. It does seem like the objtool Makefile should be hardened against CFLAGS being passed in from the command line so that the build does not break like this though. Cheers, Nathan