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 7018DC282DD for ; Tue, 7 Jan 2020 22:25:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 316F820715 for ; Tue, 7 Jan 2020 22:25:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578435915; bh=ck4c7UJ9ZG5qWrKFy9xztVIZezQr5I8+IAhGkqjM2wo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=oz9Gps1aYVdSredT4pPJeG5wg4t5dCGQW++l1ZeZ4Opo9mC91X2qwvbujpUfHg4xK WbJchyP6hp+aZjTq9sPwyvIEqeyLZedKzSA1/Ajbs6YixyyPLwDGTCqX4d7nOsBJXi f4NrBthDggAiFPCSltJqpD+9v9pjGd4Z2jwOYWis= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727256AbgAGWZO (ORCPT ); Tue, 7 Jan 2020 17:25:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:39034 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726558AbgAGWZO (ORCPT ); Tue, 7 Jan 2020 17:25:14 -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 F3DEA206DB; Tue, 7 Jan 2020 22:25:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578435913; bh=ck4c7UJ9ZG5qWrKFy9xztVIZezQr5I8+IAhGkqjM2wo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LjnYP2WtPxOf1+s588IKoPoQVbQS95f9r2Tm6C45d4QkS3w5bt0sdSroqMOUdQvpv 0kiMXWQ2G04zlLAjsQtwAVQZhAI3ggQxSYs35zfx78MEZx3H4qwXMb+q1w8VPwzJAl iZocijQ+jIbbVfEkp/KVespF2ONYI7c7xk27OxQw= Date: Tue, 7 Jan 2020 14:25:12 -0800 From: Andrew Morton To: Arnd Bergmann Cc: Oleksandr Natalenko , linux-mm@kvack.org, Arnaldo Carvalho de Melo , Will Deacon , Masami Hiramatsu , Song Liu , Alexey Dobriyan , Marc Zyngier , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] kallsyms: work around bogus -Wrestrict warning Message-Id: <20200107142512.b3d63df56ffee1ef471b6acd@linux-foundation.org> In-Reply-To: <20200107214042.855757-1-arnd@arndb.de> References: <20200107214042.855757-1-arnd@arndb.de> 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 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. > > Using sprintf() instead of strcpy() is a bit wasteful but is > the best workaround I could come up with. > > ... > > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -366,7 +366,7 @@ static int __sprint_symbol(char *buffer, unsigned long address, > return sprintf(buffer, "0x%lx", address - symbol_offset); > > if (name != buffer) > - strcpy(buffer, name); > + sprintf(buffer, "%s", name); > len = strlen(buffer); > offset -= symbol_offset; gee, is that even worth "fixing"? Oleksandr, I've seen a couple of these false positives. Do we know if anyone is taking them to the gcc developers?