From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f170.google.com (mail-pf1-f170.google.com [209.85.210.170]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id E806A42179F for ; Tue, 1 Mar 2022 19:15:09 +0100 (CET) Received: by mail-pf1-f170.google.com with SMTP id d17so15055120pfl.0 for ; Tue, 01 Mar 2022 10:15:09 -0800 (PST) Date: Tue, 1 Mar 2022 10:14:07 -0800 From: Kees Cook To: Linus Torvalds Message-ID: <202203011008.AA0B5A2D@keescook> References: <20220228110822.491923-1-jakobkoschel@gmail.com> <20220228110822.491923-3-jakobkoschel@gmail.com> <2e4e95d6-f6c9-a188-e1cd-b1eae465562a@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Cc: linux-wireless , alsa-devel@alsa-project.org, KVM list , "Gustavo A. R. Silva" , linux-iio@vger.kernel.org, nouveau@lists.freedesktop.org, Rasmus Villemoes , dri-devel , Cristiano Giuffrida , Matthew Wilcox , linux1394-devel@lists.sourceforge.net, drbd-dev@lists.linbit.com, linux-arch , CIFS , Andy Shevchenko , linux-aspeed@lists.ozlabs.org, linux-scsi , linux-rdma , linux-staging@lists.linux.dev, amd-gfx list , Jason Gunthorpe , intel-wired-lan@lists.osuosl.org, kgdb-bugreport@lists.sourceforge.net, bcm-kernel-feedback-list@broadcom.com, Dan Carpenter , Linux Media Mailing List , Arnd Bergman , Linux PM , intel-gfx , "Bos, H.J." , Nathan Chancellor , dma , Christophe JAILLET , Jakob Koschel , v9fs-developer@lists.sourceforge.net, linux-tegra , Thomas Gleixner , Brian Johannesmeyer , Linux ARM , linux-sgx@vger.kernel.org, linux-block , Netdev , linux-usb@vger.kernel.org, samba-technical@lists.samba.org, Linux Kernel Mailing List , Linux F2FS Dev Mailing List , tipc-discussion@lists.sourceforge.net, Linux Crypto Mailing List , linux-fsdevel , linux-mediatek@lists.infradead.org, Andrew Morton , linuxppc-dev , Christian =?iso-8859-1?Q?K=F6nig?= , Mike Rapoport Subject: Re: [Drbd-dev] [PATCH 2/6] treewide: remove using list iterator after loop body as a ptr List-Id: "*Coordination* of development, patches, contributions -- *Questions* \(even to developers\) go to drbd-user, please." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Feb 28, 2022 at 04:45:11PM -0800, Linus Torvalds wrote: > Really. The "-Wshadow doesn't work on the kernel" is not some new > issue, because you have to do completely insane things to the source > code to enable it. The first big glitch with -Wshadow was with shadowed global variables. GCC 4.8 fixed that, but it still yells about shadowed functions. What _almost_ works is -Wshadow=local. At first glace, all the warnings look solvable, but then one will eventually discover __wait_event() and associated macros that mix when and how deeply it intentionally shadows variables. :) Another way to try to catch misused shadow variables is -Wunused-but-set-varible, but it, too, has tons of false positives. I tried to capture some of the rationale and research here: https://github.com/KSPP/linux/issues/152 -- Kees Cook