From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f65.google.com (mail-wr1-f65.google.com [209.85.221.65]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id 6725042042B for ; Sat, 13 Jun 2020 11:59:23 +0200 (CEST) Received: by mail-wr1-f65.google.com with SMTP id y17so12257799wrn.11 for ; Sat, 13 Jun 2020 02:59:23 -0700 (PDT) Received: from soda.linbit (62-99-137-214.static.upcbusiness.at. [62.99.137.214]) by smtp.gmail.com with ESMTPSA id s7sm14114053wrr.60.2020.06.13.02.59.22 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sat, 13 Jun 2020 02:59:22 -0700 (PDT) Resent-Message-ID: <20200613095920.GM4222@soda.linbit> Received: from mail-qk1-f193.google.com (mail-qk1-f193.google.com [209.85.222.193]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id 71CCB420235 for ; Thu, 4 Jun 2020 19:58:01 +0200 (CEST) Received: by mail-qk1-f193.google.com with SMTP id w3so6995472qkb.6 for ; Thu, 04 Jun 2020 10:58:01 -0700 (PDT) Date: Thu, 4 Jun 2020 14:57:59 -0300 From: Jason Gunthorpe To: Kees Cook Message-ID: <20200604175759.GQ6578@ziepe.ca> References: <20200603233203.1695403-1-keescook@chromium.org> <20200603233203.1695403-10-keescook@chromium.org> <20200604132306.GO6578@ziepe.ca> <202006040757.0DFC3F28E@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202006040757.0DFC3F28E@keescook> Cc: Andy Whitcroft , clang-built-linux@googlegroups.com, linux-ide@vger.kernel.org, netdev@vger.kernel.org, x86@kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, linux-block@vger.kernel.org, Miguel Ojeda , linux-mm@kvack.org, Alexander Potapenko , b43-dev@lists.infradead.org, Joe Perches , Linus Torvalds , linux-clk@vger.kernel.org, drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] [PATCH 09/10] treewide: Remove uninitialized_var() usage 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 Thu, Jun 04, 2020 at 07:59:40AM -0700, Kees Cook wrote: > On Thu, Jun 04, 2020 at 10:23:06AM -0300, Jason Gunthorpe wrote: > > On Wed, Jun 03, 2020 at 04:32:02PM -0700, Kees Cook wrote: > > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > > > (or can in the future), and suppresses unrelated compiler warnings > > > (e.g. "unused variable"). If the compiler thinks it is uninitialized, > > > either simply initialize the variable or make compiler changes. > > > > > > I preparation for removing[2] the[3] macro[4], remove all remaining > > > needless uses with the following script: > > > > > > git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ > > > xargs perl -pi -e \ > > > 's/\buninitialized_var\(([^\)]+)\)/\1/g; > > > s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' > > > > > > drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid > > > pathological white-space. > > > > > > No outstanding warnings were found building allmodconfig with GCC 9.3.0 > > > for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, > > > alpha, and m68k. > > > > At least in the infiniband part I'm confident that old gcc versions > > will print warnings after this patch. > > > > As the warnings are wrong, do we care? Should old gcc maybe just -Wno- > > the warning? > > I *think* a lot of those are from -Wmaybe-uninitialized, but Linus just > turned that off unconditionally in v5.7: > 78a5255ffb6a ("Stop the ad-hoc games with -Wno-maybe-initialized") Yah, that alone is justification enough to do this purge. Jason