From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 62165C982C9 for ; Tue, 15 Sep 2026 11:37:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=fLxdQmoZZZv1r73sDolMMsAkheaSxQUZUnFqo7ivwSY=; b=0WjI9CU2hvpF2Y KZYQ/XxPBucx6wNmxv5fk7n25b2o34BX/laL2YwYRQUw1EBZXOAHi1OcgN1WJ/st+PmiJTRDIAPJV uF1RQr7E9Q/mUbTMYX/IbnBYyTjmFCnz4hAtqqT71kb5ttg1uSNd7+Tcvqp99rU+XTyTOg6QdJ3zg dN8FsG6XDzVd+76gC5fRMKhgLY/0DKDC2NNIEGqZJ2eikI60xPh3cY77Vg3jSpGxBpEEyG1Uxkrtc NON4/djWotrt4VJ1cuceOPXldj/8HWWWgqzQQkGzR9xOnXeahu0PjNhx1YjeasMnrpsSRdtVD0STa BQEMTsjiNVXlKAjc/X4A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6RTG-00000006Dfw-0mBZ; Tue, 15 Sep 2026 11:37:06 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6RSH-00000006CaE-0v4T; Tue, 15 Sep 2026 11:36:05 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id E526E418AE; Tue, 15 Sep 2026 11:36:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A1D91F00893; Tue, 15 Sep 2026 11:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789472164; bh=4BVB43/k5lHtsFkUgtZDywdRjbEBMWb9Mg6O6YdeHrM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=GYZsbVigjxwfzphIbqofaPFJmaKXOkEJuH9NfOFwlWENp60vpodSbVNNMVPrnsCGh mKkYFPjcJBJCWstEr5ZbUWw1p8gupBALyutxo/nsXoXJJVjfsUUEDeTeRzg9vNDFKw QyLxl+67I5PApcQALeqp8arjqQrJPg8lKGehuzOG7XGzc750cxvm391kPGZaHUEXVh rRpJvi2VXfCOPb4wIvdWYnRC2MlJNBFBn7hGBAKR93OKepAk7efnXRPGiZufX/FUGN bMk95QWIuEMEbgWtoC+OwCCABis9Vc8v3v1aLMq5PD8Vs1rzrsq653sDeKOiCR8bmb RSzE6TAD8kDPw== Date: Tue, 15 Sep 2026 12:35:53 +0100 From: "Lorenzo Stoakes (ARM)" To: Arnd Bergmann Cc: Linus Torvalds , Kees Cook , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?B?QmrDtnJu?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?utf-8?B?w5Z6a2Fu?= , Jonathan Corbet , Randy Dunlap , "Gustavo A. R. Silva" , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, Linux-Arch , linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe , linux-hardening@vger.kernel.org Subject: Re: [PATCH v2 00/21] kbuild: significantly speed up kernel builds Message-ID: References: <20260914-build-speedup-v2-0-39817ec5db23@kernel.org> <202609140833.88C0E16E50@keescook> <7646eb0c-7c4a-4ec2-9562-66a74c4d9858@app.fastmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <7646eb0c-7c4a-4ec2-9562-66a74c4d9858@app.fastmail.com> X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Sep 15, 2026 at 10:53:51AM +0200, Arnd Bergmann wrote: > On Mon, Sep 14, 2026, at 17:53, Linus Torvalds wrote: > > On Mon, 14 Sept 2026 at 08:41, Kees Cook wrote: > >> > >> One area I think might solved via an LLM is the 3-pass kallsyms stuff. > >> If we could get a deterministic kallsyms build in 1 pass, that would be > >> very nice. A lot of people have tried, but it has eluded upstreaming. > > > > Even the three-pass one hasn't apparently always been entirely > > deterministic. We've had random reports over the years of it failing > > in some circumstances. > > This tends to break whenever a linker (rather than the compiler) starts > creating a new type of symbols that show up in pass 2. > > > Maybe we've fixed it all, or maybe the failures just go imperceptibly > > rare. Regardless, it has definitely been fragile. > > The rate seems to be once every few years, looking at the list > of exceptions added to scripts/kallsyms.c (now scripts/mksysmap): > > efe6e3068067 ("kallsyms: fix nonconverging kallsyms table with lld") > 516d980f8541 ("scripts/kallsyms: skip ppc compiler stub *.long_branch.* / *.plt_branch.*") > b9b74be163a2 ("ARM: 8555/1: kallsyms: ignore ARM mode switching veneers") > > I'm sure there are other instances on architectures that get less > build coverage. Yeah, it's stuff like this that makes it more sensible in general to use existing tooling where that makes sense, e.g. also the .mod.S stuff. Though I also think dropping some of these arches would be a good idea ;) *ahem*. In any case, I think the bigger picture ideas like a single pass kallsyms is stuff for the future. The way I see it: grab the really low-hanging fruit (this series), then the medium-hanging fruit, and only then enter the pits of hell to fight the satanic hordes which clasp on to what remains. > > Arnd -- Cheers, Lorenzo _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv