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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 A9F04C282DD for ; Thu, 9 Jan 2020 22:02:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CA7D2077B for ; Thu, 9 Jan 2020 22:02:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578607325; bh=88y37HxDUMffX0HsWQMZbo0p/Dn1R5k39rJxWhAGkv8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=paxmzBFu1R17BT6Bx/ko+BOfNspHw+I1k5uiyENkTYudH31enFWXJe+uj4+vf3tJq sMu6nw5S3SgDXMgT29MQaTL+EoUWGfg4k9fuy6fhTmKSHMNve2NIQWCAEKsXXKXgls TRghOKfowPuMPwdM8u9FuubBXpCwKHckLCq9jYfQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729301AbgAIWCE (ORCPT ); Thu, 9 Jan 2020 17:02:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:40794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725919AbgAIWCE (ORCPT ); Thu, 9 Jan 2020 17:02:04 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3BF9F2075D; Thu, 9 Jan 2020 22:02:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578607323; bh=88y37HxDUMffX0HsWQMZbo0p/Dn1R5k39rJxWhAGkv8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RR5TIJx35kahaEVAxbdZSd2dD4wvvD8AygQIteNvGlhu412PcwBHI8AA++92FE7LS vzWA2mF2npuuF4AhWN+5xyBED2EGGDYnXNcNBvr/hY+Hz8EZplxNFIix9KXqE8N71x B3NTTHoTPXneC2tJYdwo7CNOgOrCKoT755DN3CLY= Date: Thu, 9 Jan 2020 14:02:02 -0800 From: Andrew Morton To: Masami Hiramatsu Cc: Arnd Bergmann , Oleksandr Natalenko , linux-mm@kvack.org, Arnaldo Carvalho de Melo , Will Deacon , Song Liu , Alexey Dobriyan , Marc Zyngier , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] kallsyms: work around bogus -Wrestrict warning Message-Id: <20200109140202.fd5488a2ac02f81b25d83b88@linux-foundation.org> In-Reply-To: <20200108102602.43d4c5433eb495cdbf387e9b@kernel.org> References: <20200107214042.855757-1-arnd@arndb.de> <20200108102602.43d4c5433eb495cdbf387e9b@kernel.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 8 Jan 2020 10:26:02 +0900 Masami Hiramatsu wrote: > Hi Arnd, > > On Tue, 7 Jan 2020 22:40:26 +0100 > Arnd Bergmann wrote: > > > gcc -O3 produces some really odd warnings for this file: > > > > kernel/kallsyms.c: In function 'sprint_symbol': > > kernel/kallsyms.c:369:3: error: 'strcpy' source argument is the same as destination [-Werror=restrict] > > strcpy(buffer, name); > > ^~~~~~~~~~~~~~~~~~~~ > > kernel/kallsyms.c: In function 'sprint_symbol_no_offset': > > kernel/kallsyms.c:369:3: error: 'strcpy' source argument is the same as destination [-Werror=restrict] > > strcpy(buffer, name); > > ^~~~~~~~~~~~~~~~~~~~ > > kernel/kallsyms.c: In function 'sprint_backtrace': > > kernel/kallsyms.c:369:3: error: 'strcpy' source argument is the same as destination [-Werror=restrict] > > strcpy(buffer, name); > > ^~~~~~~~~~~~~~~~~~~~ > > > > This obviously cannot be since it is preceded by an 'if (name != buffer)' > > check. > > Hmm, this looks like a bug in gcc. Yes, we're getting a lot of such reports. I don't think current gcc is ready for this patch so I'll drop it, sorry.