From patchwork Fri Feb 14 17:19:07 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: 208189 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=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 88DDDC3B1B0 for ; Fri, 14 Feb 2020 17:37:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 674692187F for ; Fri, 14 Feb 2020 17:37:58 +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="o/fbEawR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388603AbgBNRhw (ORCPT ); Fri, 14 Feb 2020 12:37:52 -0500 Received: from gateway21.websitewelcome.com ([192.185.45.155]:24527 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387544AbgBNRhw (ORCPT ); Fri, 14 Feb 2020 12:37:52 -0500 X-Greylist: delayed 1279 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Feb 2020 12:37:51 EST Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway21.websitewelcome.com (Postfix) with ESMTP id 99BFF4011BDFA for ; Fri, 14 Feb 2020 11:16:30 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 2eZqjst8vAGTX2eZqj4hVQ; Fri, 14 Feb 2020 11:16:30 -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=Hc+KXK55XGoMw2zvxQfSgUAWMXk86qqphrar4Mbwloc=; b=o/fbEawRgGH+SpYTbkk03vEU+n CgMzJmTCsdJWuzjjdxPApWm5kT9x7eqWaUHAr7mK/foulobXcF4PdipL+BC4ScgICWWbrCgZpv8IC H/paByw/b8GI3S6r9opFa0He6Wg9r+Z3L2g4vjS0OyAOrFE+TuN6BHKaW2OBEebyZs+FkK2hCJhUS TAzBR/NLsvDBCZ8hcbBcizSNauGg1WOmSylL+dsHrs5j7RXbrD6sShuXdbrEeBFjHgKcExmJXrofY BYc3lBu5esyvVu8DU8j4W31qpEuTGZGGgQwh1Ix4HoQzxYe9dDy2CHLmkE9Xuc38PqvutAZFGvX7t +CXwK18w==; Received: from [200.68.140.137] (port=3263 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j2eZp-003gzW-4C; Fri, 14 Feb 2020 11:16:29 -0600 Date: Fri, 14 Feb 2020 11:19:07 -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: gpio_keys_polled - replace zero-length array with flexible-array member Message-ID: <20200214171907.GA26588@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: 1j2eZp-003gzW-4C X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.140.137]:3263 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 25 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/gpio_keys_polled.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c index 6eb0a2f3f9de..c3937d2fc744 100644 --- a/drivers/input/keyboard/gpio_keys_polled.c +++ b/drivers/input/keyboard/gpio_keys_polled.c @@ -38,7 +38,7 @@ struct gpio_keys_polled_dev { const struct gpio_keys_platform_data *pdata; unsigned long rel_axis_seen[BITS_TO_LONGS(REL_CNT)]; unsigned long abs_axis_seen[BITS_TO_LONGS(ABS_CNT)]; - struct gpio_keys_button_data data[0]; + struct gpio_keys_button_data data[]; }; static void gpio_keys_button_event(struct input_dev *input,