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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 3622BC2D0D2 for ; Fri, 20 Dec 2019 16:42:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1749120716 for ; Fri, 20 Dec 2019 16:42:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727404AbfLTQmB (ORCPT ); Fri, 20 Dec 2019 11:42:01 -0500 Received: from vmicros1.altlinux.org ([194.107.17.57]:40554 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727181AbfLTQmA (ORCPT ); Fri, 20 Dec 2019 11:42:00 -0500 Received: from imap.altlinux.org (imap.altlinux.org [194.107.17.38]) by vmicros1.altlinux.org (Postfix) with ESMTP id E93B472CCE9; Fri, 20 Dec 2019 19:41:56 +0300 (MSK) Received: from altlinux.org (sole.flsd.net [185.75.180.6]) by imap.altlinux.org (Postfix) with ESMTPSA id B6D284A4AEF; Fri, 20 Dec 2019 19:41:56 +0300 (MSK) Date: Fri, 20 Dec 2019 19:41:56 +0300 From: Vitaly Chikunov To: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, "Dmitry V . Levin" , stable@vger.kernel.org, Vitaly Chikunov Subject: Re: [PATCH] tools lib: Disable redundant-delcs error for strlcpy Message-ID: <20191220164155.3gxstkam3ctk7kji@altlinux.org> Mail-Followup-To: Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, "Dmitry V . Levin" , stable@vger.kernel.org References: <20191208214607.20679-1-vt@altlinux.org> <20191217122331.4g5atx7in6njjlw4@altlinux.org> <20191217200420.GD7095@redhat.com> <20191220025236.kgu3v6yhjndr3zwb@altlinux.org> <20191220123136.GD2032@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191220123136.GD2032@kernel.org> User-Agent: NeoMutt/20171215-106-ac61c7 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arnaldo, On Fri, Dec 20, 2019 at 09:31:36AM -0300, Arnaldo Carvalho de Melo wrote: > Em Fri, Dec 20, 2019 at 05:52:36AM +0300, Vitaly Chikunov escreveu: > > If this is acceptable I will resend v2 with this. > > Go ahead, and please let me know if there is any container image for > Altlinux, as I test with clang on all the distros I have container > images for, and this hasn't appeared on my radar, i.e. clang + strlcpy > warnings :-) ALT Linux container micro how-to: Docker: https://en.altlinux.org/Docker Quick start: # docker run -it alt:sisyphus [root@28fd15798968 /]# apt-get update [root@28fd15798968 /]# apt-get install clang rpm-build It will install clang-7.0. systemd-nspawn: Images are at http://ftp.altlinux.org/pub/distributions/ALTLinux/images/Sisyphus/cloud/ Quick start: # machinectl pull-tar --verify=no http://ftp.altlinux.org/pub/distributions/ALTLinux/images/Sisyphus/cloud/alt-sisyphus-rootfs-systemd-x86_64.tar.xz alttest # systemd-nspawn -M alttest [root@alttest ~]# apt-get update [root@alttest ~]# apt-get install clang rpm-build There is also LXD support: https://en.altlinux.org/LXD ps. If you going to use binary clang from http://releases.llvm.org/download.html#9.0.0 I would recommend version clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-14.04.tar.xz and `ln -snf x86_64-alt-linux /usr/lib64/gcc/x86_64-unknown-linux` to workaround `cannot find -lgcc` error. Thanks, > > - Arnaldo > > > Thanks, > > > > > > > > - Arnaldo > > > > > > > 1. It seems that people putting strlcpy() into the tools was already aware of > > > > the problems it causes and tried to solve them. Probably, that's why they put > > > > `__weak` attribute on it (so it would be linkable in the presence of another > > > > strlcpy). Then `#ifndef __UCLIBC__`ed and later `#if defined(__GLIBC__) && > > > > !defined(__UCLIBC__)` its declaration. But, solution was incomplete and could > > > > be improved to make kernel buildable on more systems (where libc contains > > > > strlcpy). > > > > > > > > There is not need to make `redundant redeclaration` warning an error in > > > > this case. > > > > > > > > 2. `#pragma GCC diagnostic ignored` trick is already used multiple times > > > > in the kernel: > > > > > > > > $ git grep '#pragma GCC diagnostic ignored' > > > > arch/arm/lib/xor-neon.c:#pragma GCC diagnostic ignored "-Wunused-variable" > > > > tools/build/feature/test-gtk2-infobar.c:#pragma GCC diagnostic ignored "-Wstrict-prototypes" > > > > tools/build/feature/test-gtk2.c:#pragma GCC diagnostic ignored "-Wstrict-prototypes" > > > > tools/include/linux/string.h:#pragma GCC diagnostic ignored "-Wredundant-decls" > > > > tools/lib/bpf/libbpf.c:#pragma GCC diagnostic ignored "-Wformat-nonliteral" > > > > tools/perf/ui/gtk/gtk.h:#pragma GCC diagnostic ignored "-Wstrict-prototypes" > > > > tools/testing/selftests/kvm/lib/assert.c:#pragma GCC diagnostic ignored "-Wunused-result" > > > > tools/usb/ffs-test.c:#pragma GCC diagnostic ignored "-Wdeprecated-declarations" > > > > > > > > So the solution does not seem alien in the kernel and should be acceptable. > > > > > > > > (I also send this to another of your emails in case I used wrong one before.) > > > > > > > > Thanks, > > > > > > > > > > > > On Mon, Dec 09, 2019 at 12:46:07AM +0300, Vitaly Chikunov wrote: > > > > > Disable `redundant-decls' error for strlcpy declaration and solve build > > > > > error allowing users to compile vanilla kernels. > > > > > > > > > > When glibc have strlcpy (such as in ALT linux since 2004) objtool and > > > > > perf build fails with something like: > > > > > > > > > > In file included from exec-cmd.c:3: > > > > > tools/include/linux/string.h:20:15: error: redundant redeclaration of ‘strlcpy’ [-Werror=redundant-decls] > > > > > 20 | extern size_t strlcpy(char *dest, const char *src, size_t size); > > > > > | ^~~~~~~ > > > > > > > > > > It's very hard to produce a perfect fix for that since it is a header > > > > > file indirectly pulled from many sources from different Makefile builds. > > > > > > > > > > Fixes: ce99091 ("perf tools: Move strlcpy() from perf to tools/lib/string.c") > > > > > Fixes: 0215d59 ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__") > > > > > Signed-off-by: Vitaly Chikunov > > > > > Cc: Dmitry V. Levin > > > > > Cc: Josh Poimboeuf > > > > > Cc: Vineet Gupta > > > > > Cc: stable@vger.kernel.org > > > > > --- > > > > > tools/include/linux/string.h | 3 +++ > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h > > > > > index 980cb9266718..99ede7f5dfb8 100644 > > > > > --- a/tools/include/linux/string.h > > > > > +++ b/tools/include/linux/string.h > > > > > @@ -17,7 +17,10 @@ int strtobool(const char *s, bool *res); > > > > > * However uClibc headers also define __GLIBC__ hence the hack below > > > > > */ > > > > > #if defined(__GLIBC__) && !defined(__UCLIBC__) > > > > > +#pragma GCC diagnostic push > > > > > +#pragma GCC diagnostic ignored "-Wredundant-decls" > > > > > extern size_t strlcpy(char *dest, const char *src, size_t size); > > > > > +#pragma GCC diagnostic pop > > > > > #endif > > > > > > > > > > char *str_error_r(int errnum, char *buf, size_t buflen); > > > > > -- > > - Arnaldo