From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934607AbdGTIRZ (ORCPT ); Thu, 20 Jul 2017 04:17:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39930 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933880AbdGTIRV (ORCPT ); Thu, 20 Jul 2017 04:17:21 -0400 Date: Thu, 20 Jul 2017 10:17:12 +0200 From: gregkh To: Arnd Bergmann Cc: Andrew Morton , mm-commits@vger.kernel.org, Linus Torvalds , Linux Kernel Mailing List , Linux Kbuild mailing list , stable Subject: Re: + kbuild-disable-wformat-truncation-warnings-by-default.patch added to -mm tree Message-ID: <20170720081712.GA11963@kroah.com> References: <596fd414.fDkQ2LPtuAl0Zq0f%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 20, 2017 at 09:24:21AM +0200, Arnd Bergmann wrote: > On Wed, Jul 19, 2017 at 11:50 PM, wrote: > > ------------------------------------------------------ > > From: Arnd Bergmann > > Subject: kbuild: disable -Wformat-truncation warnings by default > > > > With x86 allmodconfig, we currently get 233 -Wformat-truncation warnings, > > which makes the entire warnings rather useless. > > > > This turns off the warning by default, unless we specify W=1 or higher > > > > Link: http://lkml.kernel.org/r/20170714120720.906842-2-arnd@arndb.de > > Signed-off-by: Arnd Bergmann > > Signed-off-by: Andrew Morton > > --- > > > > scripts/Makefile.extrawarn | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff -puN scripts/Makefile.extrawarn~kbuild-disable-wformat-truncation-warnings-by-default scripts/Makefile.extrawarn > > --- a/scripts/Makefile.extrawarn~kbuild-disable-wformat-truncation-warnings-by-default > > +++ a/scripts/Makefile.extrawarn > > @@ -67,5 +67,8 @@ KBUILD_CFLAGS += $(call cc-disable-warni > > KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare) > > KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length) > > KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized) > > +else > > +# noisy gcc-7 warnings > > +KBUILD_CFLAGS += $(call cc-option,-Wformat-truncation=0) > > endif > > endif > > Hi Andrew, Linus, Greg, > > I noticed that Linus has made a similar patch in 4.13-rc1, commit bd664f6b3e37 > ("disable new gcc-7.1.1 warnings for now"), and it completely disables three > warnings (format-truncation, format-overflow and int-in-bool-context). > > Obviously there is no point in having both, so let's talk about what we > want for 4.13, stable-backports and for future kernels, I'll then send those > patches. Here is my first suggestion: > > - enable all three warnings with "make W=1" in 4.13, but leave them > disabled by default. > - backport Linus' patch, plus the follow-up for W=1 to stable kernels, > to allow stable kernels to build cleanly I don't care which of these, I'll take whatever is in Linus's tree. And I'll go backport that patch now as I'm getting annoyed by the warnings at the moment... > - backport the patches that address any other gcc-7 warnings, as > well as those that are not obvious false-positives to stable kernels I'll do that as well, as I notice them go by. > - In 4.14+, use my version above and address all int-in-bool-context > and format-overflow warnings, but only use -Wformat-truncation > with make W=1. I don't really care about this, as long as we are not forced to do "silly things" like some of the patches seemed to do :) thanks, greg k-h