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 B0E5BC71156 for ; Sun, 22 Nov 2020 22:11:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84EC52078D for ; Sun, 22 Nov 2020 22:11:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726651AbgKVWLB (ORCPT ); Sun, 22 Nov 2020 17:11:01 -0500 Received: from asavdk4.altibox.net ([109.247.116.15]:51724 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbgKVWK6 (ORCPT ); Sun, 22 Nov 2020 17:10:58 -0500 Received: from ravnborg.org (unknown [188.228.123.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id 2C52280567; Sun, 22 Nov 2020 23:10:42 +0100 (CET) Date: Sun, 22 Nov 2020 23:10:40 +0100 From: Sam Ravnborg To: James Bottomley Cc: Kees Cook , 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@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, 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, Nick Desaulniers , 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@lists.freedesktop.org, 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@vger.kernel.org, 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, target-devel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hwmon@vger.kernel.org, x86@kernel.org, linux-nfs@vger.kernel.org, GR-Linux-NIC-Dev@marvell.com, linux-mm@kvack.org, netdev@vger.kernel.org, linux-decnet-user@lists.sourceforge.net, linux-mmc@vger.kernel.org, "Gustavo A. R. Silva" , linux-renesas-soc@vger.kernel.org, linux-sctp@vger.kernel.org, linux-usb@vger.kernel.org, netfilter-devel@vger.kernel.org, linux-crypto@vger.kernel.org, patches@opensource.cirrus.com, Joe Perches , linux-integrity@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH 000/141] Fix fall-through warnings for Clang Message-ID: <20201122221040.GD566387@ravnborg.org> References: <20201120105344.4345c14e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <202011201129.B13FDB3C@keescook> <20201120115142.292999b2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <202011220816.8B6591A@keescook> <9b57fd4914b46f38d54087d75e072d6e947cb56d.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9b57fd4914b46f38d54087d75e072d6e947cb56d.camel@HansenPartnership.com> X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=VafZwmh9 c=1 sm=1 tr=0 a=S6zTFyMACwkrwXSdXUNehg==:117 a=S6zTFyMACwkrwXSdXUNehg==:17 a=kj9zAlcOel0A:10 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=7T594MSkF3521FIrX4wA:9 a=CjuIK1q_8ugA:10 a=AjGcO6oz07-iQ99wixmX:22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi James. > > > If none of the 140 patches here fix a real bug, and there is no > > > change to machine code then it sounds to me like a W=2 kind of a > > > warning. > > > > FWIW, this series has found at least one bug so far: > > https://lore.kernel.org/lkml/CAFCwf11izHF=g1mGry1fE5kvFFFrxzhPSM6qKAO8gxSp=Kr_CQ@mail.gmail.com/ > > > Well, it's a problem in an error leg, sure, but it's not a really > compelling reason for a 141 patch series, is it? All that fixing this > error will do is get the driver to print "oh dear there's a problem" > under four more conditions than it previously did. You are asking the wrong question here. Yuo should ask how many hours could have been saved by all the bugs people have been fighting with and then fixed *before* the code hit the kernel at all. My personal experience is that I, more than once, have had errors related to a missing break in my code. So this warnings is IMO a win. And if we are only ~100 patches to have it globally enabled then it is a no-brainer in my book. Sam