From patchwork Fri Feb 14 17:20:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 208190 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 5037DC2BA83 for ; Fri, 14 Feb 2020 17:17:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25EAC206CC for ; Fri, 14 Feb 2020 17:17:49 +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="qs/HLk5w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394651AbgBNRRr (ORCPT ); Fri, 14 Feb 2020 12:17:47 -0500 Received: from gateway33.websitewelcome.com ([192.185.146.80]:21083 "EHLO gateway33.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394642AbgBNRRr (ORCPT ); Fri, 14 Feb 2020 12:17:47 -0500 Received: from cm11.websitewelcome.com (cm11.websitewelcome.com [100.42.49.5]) by gateway33.websitewelcome.com (Postfix) with ESMTP id 31F221C035 for ; Fri, 14 Feb 2020 11:17:46 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 2eb4jOxK6Sl8q2eb4j74tA; Fri, 14 Feb 2020 11:17:46 -0600 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=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:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=WdyaSABb4nKRDgvU/3FE2JdQX1c2NVD5ZKrARuHcShM=; b=qs/HLk5wau6g/8LIk47qnzlbnJ zGHUfSrcnyz12L9l+y0IWzynMRmB0VCGylL+HkeNO70QQ9OFfhbFu0ch4PbLkNuljJW+kQJ36TnTO 2d6J6raQp9pd07yE6zJh3bpvWsBBmnORokFdr6rku6ttEzsIvcl8N31N7JeCpj5cCOIS2JCwmrbjb 5CDsrFarF7OGlPOMR+5Pet9GRcVUbnUrk+16rWdrwh6g3bFONmKBvVNnWnVnahz0LnHO3tmZmjucV wRLei6IixqBJfOJZirvPj+3aPN84/CoXbenFEVQqvnok14+azd6D7bmblmV6b1Mbz5XWJZmpxL/jy V9+PMaOg==; Received: from [200.68.140.137] (port=19663 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j2eb2-003hYb-Lo; Fri, 14 Feb 2020 11:17:44 -0600 Date: Fri, 14 Feb 2020 11:20:22 -0600 From: "Gustavo A. R. Silva" To: Dmitry Torokhov Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] Input: tca6416-keypad - replace zero-length array with flexible-array member Message-ID: <20200214172022.GA27490@embeddedor> MIME-Version: 1.0 Content-Disposition: inline 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: 200.68.140.137 X-Source-L: No X-Exim-ID: 1j2eb2-003hYb-Lo X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.140.137]:19663 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 28 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@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 --- drivers/input/keyboard/tca6416-keypad.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/input/keyboard/tca6416-keypad.c b/drivers/input/keyboard/tca6416-keypad.c index 2a14769de637..21758767ccf0 100644 --- a/drivers/input/keyboard/tca6416-keypad.c +++ b/drivers/input/keyboard/tca6416-keypad.c @@ -33,7 +33,7 @@ MODULE_DEVICE_TABLE(i2c, tca6416_id); struct tca6416_drv_data { struct input_dev *input; - struct tca6416_button data[0]; + struct tca6416_button data[]; }; struct tca6416_keypad_chip { @@ -48,7 +48,7 @@ struct tca6416_keypad_chip { int irqnum; u16 pinmask; bool use_polling; - struct tca6416_button buttons[0]; + struct tca6416_button buttons[]; }; static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)