From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 907D1362152 for ; Wed, 17 Dec 2025 13:22:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765977744; cv=none; b=F0Sny0B4FLEpx1/09mRnCKIvpxcTKUwWoMUbMLYs5ClqOv+RjOnTz8PQimc3bd3Az1OWq1T0MKHeDxeLD21CK7eRHXlNddiJGteaW7MuH7+HZWQ2jc+sAjv8/OA3XZihwOmd/y/2B5jPhTXQZ1yxccQPyoHNQ5a8pRgNEGkOdXs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765977744; c=relaxed/simple; bh=3Ijbh/nPoDWyl1wqO+j6n13SM8OwSJUw9+wc0+G7sk0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pk6w2gMUMTkgH9fbzDN0rKMZIInSt0DfrkosZziS3fDGLanPMlXfx/5pbqg1gPcKajdbOdBvAOzbFOjUVe3hTFuZCXu22oetYwjogsdGrpVqdEGd+haTjNd9H/8FCbRDCkbj6J2WAi8r3AGacesu/bFjOAJmIH0HF+o8ct/mgbY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=dItZW4R1; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="dItZW4R1" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=S/mIdoply3FBpTaOmN7Aj+vuGFcIr6N2ijlyPOpxRbY=; b=dItZW4R1uhUhTl/FoPHFhInFJv aKb7Ab+jS9rGkDgmNpMNRhR0kXcFCpyaIcITMuqp2cc3s6KNsmRiYbi8RQj9kQNNvJckmG0eKzwvs JPl3vOetWXdSXoHyqw6gK46WBu8PsMGOsVkGJiFsn+V3J0RPDxqtN7sWTW4gWNeHFHWDhLpCXIpzn bUQUSWIC4QECZEmRd27eCBYOtTriGji14P0RIGbHqtEE4syjQgoAfXkI3J13/o+kX0s4ELog80A04 cRHjG0tkL2QkBz+W9ACjIr2VKLsispszdA2xR56PE2FQTZ32KpboeAU+kHOMLbqCC8aGEfEoo9A/P WSOKs8OA==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vVrTu-00000004kZz-0Th7; Wed, 17 Dec 2025 13:22:18 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 1E8CF3005E0; Wed, 17 Dec 2025 14:22:17 +0100 (CET) Date: Wed, 17 Dec 2025 14:22:17 +0100 From: Peter Zijlstra To: Jean Delvare Cc: LKML Subject: Re: Build breakage caused by the use of UDB Message-ID: <20251217132217.GF3707891@noisy.programming.kicks-ass.net> References: <20251217124119.5832bba7@endymion> <20251217123536.GE3707891@noisy.programming.kicks-ass.net> <20251217124713.GD3708021@noisy.programming.kicks-ass.net> <20251217141037.2dff77b8@endymion> 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: <20251217141037.2dff77b8@endymion> On Wed, Dec 17, 2025 at 02:10:37PM +0100, Jean Delvare wrote: > Hi Peter, > > On Wed, 17 Dec 2025 13:47:13 +0100, Peter Zijlstra wrote: > > On Wed, Dec 17, 2025 at 01:35:36PM +0100, Peter Zijlstra wrote: > > > On Wed, Dec 17, 2025 at 12:44:23PM +0100, Jean Delvare wrote: > > > > I must confess this is all way beyond me and I have no idea how this > > > > change can cause such a build failure, but it does. If it matters, my > > > > compiler is gcc 8.2.1. > > > > > > Well, that is somewhat unexpected. None of the build robots fingered > > > this. Is there a particular .config I should try? > > > > > > I don't seem to have 8.2.1 at hand, but I'll try with 8.3.0. > > > > I had to (obviously) enable the RTL8192 bits, but then, yes. gcc-8 fails > > to build this while gcc-10 doesn't seem to have any problems (for some > > reason my random dev machine of the day doesn't seem to have gcc-9). > > As an additional data point, clang 17.0.6 builds the kernel just fine > for me. Yeah, everything except gcc-8 so far. It really is a weird compiler issue. > > Let me prod at this for a bit. But also, is there a good reason you're > > using this stone-age compiler? :-) And yes, its our minimum supported, > > so I suppose I should go fix, but other than build testing, you really > > shoulnd't be using it. > > Actually the default C compiler on my openSUSE Leap 15.6 system is even > gcc 7, I had to manually install gcc 8 and use CC= because gcc 7 is no > longer supported for upstream kernel builds. I think Leap only changes > the default compiler on major version changes, and Leap 15.0 was > released 7.5 years ago. > > If gcc 8 is considered too old, that's fine with me, I can switch to > yet another compiler, but then Documentation/process/changes.rst should > be updated to reflect that. As long as our documentation says a > compiler is supported, I am willing to use it to verify if that's > actually true ;-) So strictly speaking gcc-8 should indeed build the kernel, and I'll try and make this thing go away. But even so, you'll not get the best possible kernel with gcc-8, it misses a ton of features. I'm not saying you should move to gcc-16, but keeping up with the compiler isn't a bad idea in general.