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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27929C433E1 for ; Sun, 12 Jul 2020 19:40:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0745220702 for ; Sun, 12 Jul 2020 19:40:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729312AbgGLTjy (ORCPT ); Sun, 12 Jul 2020 15:39:54 -0400 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:46027 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729213AbgGLTjy (ORCPT ); Sun, 12 Jul 2020 15:39:54 -0400 X-Originating-IP: 50.39.163.217 Received: from localhost (50-39-163-217.bvtn.or.frontiernet.net [50.39.163.217]) (Authenticated sender: josh@joshtriplett.org) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id E2F421BF205; Sun, 12 Jul 2020 19:39:46 +0000 (UTC) Date: Sun, 12 Jul 2020 12:39:44 -0700 From: Josh Triplett To: Adrian Bunk Cc: Nick Desaulniers , alex.gaynor@gmail.com, geofft@ldpreload.com, jbaublitz@redhat.com, Masahiro Yamada , Linus Torvalds , Greg KH , Miguel Ojeda , Steven Rostedt , LKML , clang-built-linux Subject: Re: Linux kernel in-tree Rust support Message-ID: <20200712193944.GA81641@localhost> References: <20200712123151.GB25970@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200712123151.GB25970@localhost> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 12, 2020 at 03:31:51PM +0300, Adrian Bunk wrote: > On Thu, Jul 09, 2020 at 11:41:47AM -0700, Nick Desaulniers wrote: > >... > > but also a larger question of "should we do > > this?" or "how might we place limits on where this can be used?" > >... > > I won't attend, but I do have a topic that should be covered: > > Firefox always depends on recent Rust, which forces distributions to > update Rust in stable releases. > > As an example: > Ubuntu LTS releases upgrade to a new Rust version every 1-2 months. > Ubuntu 16.04 started with Rust 1.7.0 and is now at Rust 1.41.0. > > It would not sound good to me if security updates of distribution > kernels might additionally end up using a different version of the > Rust compiler - the toolchain for the kernel should be stable. > > Would Rust usage in the kernel require distributions to ship > a "Rust for Firefox" and a "Rust for the kernel"? Rust has hard stability guarantees when upgrading from one stable version to the next. If code compiles with a given stable version of Rust, it'll compile with a newer stable version of Rust. Given that, a stable distribution will just need a single sufficiently up-to-date Rust that meets the minimum version requirements of both Firefox and Linux. (That would not apply if the kernel used nightly Rust, since nightly-only features are allowed to change before becoming stable; that's one reason why we should use stable Rust, and try to get Firefox to stick to stable Rust.)