From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754010AbbJNOMA (ORCPT ); Wed, 14 Oct 2015 10:12:00 -0400 Received: from mx2.parallels.com ([199.115.105.18]:46183 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814AbbJNOL5 (ORCPT ); Wed, 14 Oct 2015 10:11:57 -0400 Subject: Re: [PATCH v2 1/2] Provide READ_ONCE_NOCHECK() To: Ingo Molnar References: <201510140014.WiiJdkpM%fengguang.wu@intel.com> <561D31F0.4080106@virtuozzo.com> <20151014134047.GA10316@gmail.com> CC: kbuild test robot , , , Thomas Gleixner , "H. Peter Anvin" , , Andrew Morton , Andy Lutomirski , Andrey Konovalov , Kostya Serebryany , Alexander Potapenko , kasan-dev , Borislav Petkov , Denys Vlasenko , Andi Kleen , Dmitry Vyukov , Sasha Levin , Wolfram Gloger From: Andrey Ryabinin Message-ID: <561E62A2.3070608@virtuozzo.com> Date: Wed, 14 Oct 2015 17:11:46 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20151014134047.GA10316@gmail.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: US-EXCH.sw.swsoft.com (10.255.249.47) To US-EXCH.sw.swsoft.com (10.255.249.47) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/14/2015 04:40 PM, Ingo Molnar wrote: > > * Andrey Ryabinin wrote: > >> >> >> On 10/13/2015 07:02 PM, kbuild test robot wrote: >>> Hi Andrey, >>> >>> [auto build test WARNING on tip/auto-latest -- if it's inappropriate base, please suggest rules for selecting the more suitable base] >>> >>> url: https://github.com/0day-ci/linux/commits/Andrey-Ryabinin/Provide-READ_ONCE_NOCHECK/20151013-204127 >>> config: mn10300-allyesconfig (attached as .config) >>> reproduce: >>> wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross >>> chmod +x ~/bin/make.cross >>> # save the attached .config to linux build tree >>> make.cross ARCH=mn10300 >>> >>> All warnings (new ones prefixed by >>): >>> >>> fs/nfs/filelayout/filelayout.c: In function 'filelayout_read_pagelist': >>> fs/nfs/filelayout/filelayout.c:476:2: warning: format '%Zu' expects argument of type 'size_t', but argument 5 has type '__u32' [-Wformat=] >>> dprintk("--> %s ino %lu pgbase %u req %Zu@%llu\n", >>> ^ >> >> So the actual warning is here. And it's not new. >> >>> In file included from include/linux/nfs_fs.h:28:0, >>> from fs/nfs/filelayout/filelayout.c:32: >>> fs/nfs/filelayout/filelayout.c: In function 'filelayout_write_pagelist': >>> include/linux/compiler.h:270:8: warning: format '%Zu' expects argument of type 'size_t', but argument 5 has type '__u32' [-Wformat=] >>> union { typeof(x) __val; char __c[1]; } __u; \ >>> ^ >>> include/linux/sunrpc/debug.h:33:24: note: in definition of macro 'dfprintk' >>> printk(KERN_DEFAULT args); \ >>> ^ >>>>> include/linux/compiler.h:274:22: note: in expansion of macro '__READ_ONCE' >>> #define READ_ONCE(x) __READ_ONCE(x, _check) >>> ^ >> >> And this 'note: in expansion of macro' belongs to the warning above. >> So it's a false-positive. > > So if this is a new warning introduced by these patches then the warning needs to > be addresses It's not a new warning. It's a new 'note: in expansion of macro' message which is belongs to the old warning from above. I changed the macros, so obviously it caused change in macro expansion backtrace. The actual warning existed before this patch. > - regardless of whether it's a false positive or not. I wasn't very clear. By false positive I meant that it is kbuild robot's false positive. The warning itself is not a false positive, but it's an old warning, it's not introduced by this patch. It seems that kbuild robot treats 'note: in expansion of macro' message as a new warning, but such messages are not warnings by itself. I think, that kbuild robot should just ignore new 'note: in expansion of macro' messages unless these messages preceded by a new 'warning:' message. > Thanks, > > Ingo >