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=-13.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 E01CDC3A5A0 for ; Mon, 20 Apr 2020 18:09:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B41C82071C for ; Mon, 20 Apr 2020 18:09:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="tNk46QkH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727824AbgDTSJz (ORCPT ); Mon, 20 Apr 2020 14:09:55 -0400 Received: from gateway33.websitewelcome.com ([192.185.146.80]:22723 "EHLO gateway33.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726013AbgDTSJy (ORCPT ); Mon, 20 Apr 2020 14:09:54 -0400 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway33.websitewelcome.com (Postfix) with ESMTP id B48A72848A for ; Mon, 20 Apr 2020 13:09:52 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id Qargj4g9sXVkQQargjFtPS; Mon, 20 Apr 2020 13:09:52 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=In-Reply-To:Content-Type:MIME-Version: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:References:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=wJHD7TM3Fxu768MV0g98UB0HrQgL7g1TGpW7kc7eYmA=; b=tNk46QkHwbkRhl/pIcS2wG+G02 odFVU+69XYalTXZ55cswb2uY9LTYg1AEqtqpo9b3/S5mIVFEKMATcgSc24hrX3zvXLMZqD34wVlyr F/S0uYUIIyY0zom6YAhFTwAwa904HAVlvCRvOuo3QqfHxC4TfpbsbZRd+s5kBiCSgiBbYxlKJxr7d HIpwG2vPDiQKSKftvnXky++w/poyCBovxQnoPy0C164JiN+WDau9x5cWfsdKluft6KZzlM7KXfw3u iF5O65eIjTpjA1zu1uStxusQYJX7souRp4akcRbIR+cabjI6lB5k2zcz0HgetteNKJdyR47nYmUDC QlhL/NLA==; Received: from [201.166.169.58] (port=24020 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jQarf-0043yr-CF; Mon, 20 Apr 2020 13:09:51 -0500 Date: Mon, 20 Apr 2020 13:14:01 -0500 From: "Gustavo A. R. Silva" To: Geert Uytterhoeven , "Gustavo A. R. Silva" Cc: linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org Subject: [PATCH RESEND 1/2][next] m68k: amiga: config: Replace zero-length array with flexible-array member Message-ID: <20200420181401.GA32172@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 201.166.169.58 X-Source-L: No X-Exim-ID: 1jQarf-0043yr-CF X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.169.58]:24020 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- arch/m68k/amiga/config.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c index c32ab8041cf6..06c15374200e 100644 --- a/arch/m68k/amiga/config.c +++ b/arch/m68k/amiga/config.c @@ -628,7 +628,7 @@ struct savekmsg { unsigned long magic2; /* SAVEKMSG_MAGIC2 */ unsigned long magicptr; /* address of magic1 */ unsigned long size; - char data[0]; + char data[]; }; static struct savekmsg *savekmsg; -- 2.26.0