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=-3.8 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 32824C6379D for ; Wed, 25 Nov 2020 21:33:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08363206E0 for ; Wed, 25 Nov 2020 21:33:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732357AbgKYVdf (ORCPT ); Wed, 25 Nov 2020 16:33:35 -0500 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:38476 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730364AbgKYVdc (ORCPT ); Wed, 25 Nov 2020 16:33:32 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by kvm5.telegraphics.com.au (Postfix) with ESMTP id 9789F29FB0; Wed, 25 Nov 2020 16:33:24 -0500 (EST) Date: Thu, 26 Nov 2020 08:33:24 +1100 (AEDT) From: Finn Thain To: Nick Desaulniers cc: James Bottomley , Kees Cook , "Gustavo A. R. Silva" , Joe Perches , Jakub Kicinski , alsa-devel@alsa-project.org, linux-atm-general@lists.sourceforge.net, reiserfs-devel@vger.kernel.org, linux-iio@vger.kernel.org, linux-wireless , linux-fbdev@vger.kernel.org, dri-devel , LKML , Nathan Chancellor , linux-ide@vger.kernel.org, dm-devel@redhat.com, keyrings@vger.kernel.org, linux-mtd@lists.infradead.org, GR-everest-linux-l2@marvell.com, wcn36xx@lists.infradead.org, samba-technical@lists.samba.org, linux-i3c@lists.infradead.org, linux1394-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, usb-storage@lists.one-eyed-alien.net, drbd-dev@lists.linbit.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, rds-devel@oss.oracle.com, linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org, oss-drivers@netronome.com, bridge@lists.linux-foundation.org, linux-security-module@vger.kernel.org, amd-gfx list , linux-stm32@st-md-mailman.stormreply.com, cluster-devel@redhat.com, linux-acpi@vger.kernel.org, coreteam@netfilter.org, intel-wired-lan@lists.osuosl.org, linux-input@vger.kernel.org, Miguel Ojeda , tipc-discussion@lists.sourceforge.net, linux-ext4@vger.kernel.org, linux-media@vger.kernel.org, linux-watchdog@vger.kernel.org, selinux@vger.kernel.org, linux-arm-msm , intel-gfx@lists.freedesktop.org, linux-geode@lists.infradead.org, linux-can@vger.kernel.org, linux-block@vger.kernel.org, linux-gpio@vger.kernel.org, op-tee@lists.trustedfirmware.org, linux-mediatek@lists.infradead.org, xen-devel@lists.xenproject.org, nouveau@lists.freedesktop.org, linux-hams@vger.kernel.org, ceph-devel@vger.kernel.org, virtualization@lists.linux-foundation.org, Linux ARM , linux-hwmon@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , linux-nfs@vger.kernel.org, GR-Linux-NIC-Dev@marvell.com, Linux Memory Management List , Network Development , linux-decnet-user@lists.sourceforge.net, linux-mmc@vger.kernel.org, Linux-Renesas , linux-sctp@vger.kernel.org, linux-usb@vger.kernel.org, netfilter-devel@vger.kernel.org, "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , patches@opensource.cirrus.com, linux-integrity@vger.kernel.org, target-devel@vger.kernel.org, linux-hardening@vger.kernel.org, Jonathan Cameron , Greg KH Subject: Re: [Intel-wired-lan] [PATCH 000/141] Fix fall-through warnings for Clang In-Reply-To: Message-ID: References: <202011201129.B13FDB3C@keescook> <20201120115142.292999b2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <202011220816.8B6591A@keescook> <9b57fd4914b46f38d54087d75e072d6e947cb56d.camel@HansenPartnership.com> <0147972a72bc13f3629de8a32dee6f1f308994b5.camel@HansenPartnership.com> <20201123130348.GA3119@embeddedor> <8f5611bb015e044fa1c0a48147293923c2d904e4.camel@HansenPartnership.com> <202011241327.BB28F12F6@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-sctp@vger.kernel.org On Wed, 25 Nov 2020, Nick Desaulniers wrote: > So developers and distributions using Clang can't have > -Wimplicit-fallthrough enabled because GCC is less strict (which has > been shown in this thread to lead to bugs)? We'd like to have nice > things too, you know. > Apparently the GCC developers don't want you to have "nice things" either. Do you think that the kernel should drop gcc in favour of clang? Or do you think that a codebase can somehow satisfy multiple checkers and their divergent interpretations of the language spec? > This is not a shiny new warning; it's already on for GCC and has existed > in both compilers for multiple releases. > Perhaps you're referring to the compiler feature that lead to the ill-fated, tree-wide /* fallthrough */ patch series. When the ink dries on the C23 language spec and the implementations figure out how to interpret it then sure, enforce the warning for new code -- the cost/benefit analysis is straight forward. However, the case for patching existing mature code is another story.