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 A6CE61C84CB for ; Sat, 24 Jan 2026 19:40:32 +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=1769283632; cv=none; b=FebrXjkkx8bqoMufYzgwLWC3kaXzJOa5MRfI4QEj5gZ1Do/AJfe0PYjueneIG5o2kacoGk9Na4zBlrJb5UNok/ovWX6rj32/9Y1Z5IA1ZkEepmxK1e1UecMBT/+P9Zy6q1OKQyLz/ARTTNJlbZPSQCF1iNDidwpUhbk61l+FYAE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769283632; c=relaxed/simple; bh=JzgGaoqhFcr+mQ+edMrcacm5xDkQgBC2RkwsE8+1KNk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Gs5896bSIznPUdJG7+Pim4w8nCff/IEmDBRmlqQIHSdoqR1JKV2gOpG3oRjFcsFEg1hMjYtPzonXNHYgfQ92o0SU7CLDWJTgB1aXOCul0xxldtlwc1rm3dHKsNeUb5dd6pvflZJygw9lLIpNaYMFO9W3it1W4P/9y7yQpjVAqIE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hMG5/o3C; 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="hMG5/o3C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2990C116D0; Sat, 24 Jan 2026 19:40:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769283632; bh=JzgGaoqhFcr+mQ+edMrcacm5xDkQgBC2RkwsE8+1KNk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hMG5/o3CECvPsCgLRq8t1zMw1V6MZ499WHVlK/jSQYFHSkVON8XF2HwXwaZVtvLMI qMPJQmuLhI1dNXQkhsm4EhznlegjoVDp6e7uEBI6byzdaYMqZol4uY+IpI53GfPBm5 OKV+JCvgvdPDwh5s1YvjMSVe01O5MYirGGxso/plK5gi6Mm1/j+J9ZaR1LUvNnsJee NokU642ZoblV5kmTMgrYFzygFTIvbqky5ZEPmujGYtAUn2BZ+bYIgmuo9QvJ9KDC+K Vv5lvY+FlOfoJHMTTiY8okILC9I859egt7Tg+J0Dq9D4GZg0+aYEfrouyWd034bhgx uxx8BNHfLxXRA== Date: Sat, 24 Jan 2026 20:36:24 +0100 From: Nicolas Schier To: Song Liu Cc: Nathan Chancellor , linux-kbuild@vger.kernel.org Subject: Re: make olddefconfig surprises Message-ID: Mail-Followup-To: Song Liu , Nathan Chancellor , linux-kbuild@vger.kernel.org References: <20260123205359.GA95167@ax162> <20260123234418.GA206716@ax162> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Jan 23, 2026 at 03:57:59PM -0800, Song Liu wrote: > On Fri, Jan 23, 2026 at 3:44 PM Nathan Chancellor wrote: > [...] > > I do not think something like this exists (maybe a SAT solver? :P), at > > least not as part of the kernel tree. This is basically the same thing > > as not being able to turn on a configuration in menuconfig until you > > have gone through and enabled all of its dependencies. I personally use > > menuconfig when trying to create a configuration fragment for minimized > > reproducers on top of defconfigs because it is easy to see the final > > diff when everything is switched: > > > > $ make defconfig > > $ make menuconfig > > $ git diff --no-index .config.old .config > > I also use menuconfig to figure out the dependencies. The problem of > this approach is that, if defconfig changes, specifically, if a dependency > is changed from y to n in defconfig, the fragment may stop working. > IOW, the fragment assumes some dependency is enabled by default, > but there is no guarantee that the dependency will always be y in > defconfig. This should happen rarely though. > > I guess figuring out all dependencies is not too difficult? But I guess > the reward is not very big either. > > > You could start with defconfig or a more minimal configuration like > > allnoconfig depending on how the selftests config is expected to be > > used (as a base or merged into other configs). > > Thanks for sharing these tips. > > Song > Have you tried to use something like make KCONFIG_ALLCONFIG=whatever/minimal.config make allnoconfig ? Kind regards, Nicolas