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 076E6C3F2D1 for ; Mon, 2 Mar 2020 21:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CC95E22B48 for ; Mon, 2 Mar 2020 21:01:39 +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="qbLLolwo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726747AbgCBVBi (ORCPT ); Mon, 2 Mar 2020 16:01:38 -0500 Received: from gateway34.websitewelcome.com ([192.185.149.77]:40926 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725911AbgCBVBi (ORCPT ); Mon, 2 Mar 2020 16:01:38 -0500 Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 2F2F19AABDF for ; Mon, 2 Mar 2020 15:01:37 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 8sC1jgHm9vBMd8sC1jb6Fi; Mon, 02 Mar 2020 15:01:37 -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=zN3rMtGrk/Zs5GdX97JZqsBoFoWxHWo9zxihuTDfHA0=; b=qbLLolwoTYSiwhnOJDcHHRchiL X8Tnxyqk7vYdE/ErRr7J2QChPJTT/FCLEt5Zhl3g5breiKvoIbPjoKG0wqeyfWAgqcn4hoS8XPSBg YfI7ZLZnQpDJAKaYtQOkYcx7rmrqPEMx+LKNoB8G9p/1q7TiVEXhslR1w3id/Zkkfvn/+LzJkro2O qe3CzdrzteN1gu1PKoS8Kmi7yPj+svFQSC5ZR8TDGQk4kJ5TqnNrx7AyAvX7o5oBcyAHPmka3XsOq 8/2/Xq/jcnYZp6WL2Ffjn0yRldfDiU3zIOW3qWcH+eiJn7hIYv/mco1DZWUS653vmbxdCoNPjeHmb QS1sO7GA==; Received: from [201.166.169.19] (port=16672 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j8sBz-0004O8-4B; Mon, 02 Mar 2020 15:01:35 -0600 Date: Mon, 2 Mar 2020 15:04:37 -0600 From: "Gustavo A. R. Silva" To: "mlxsw@mellanox.com David S. Miller" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] net: mlxfw: Replace zero-length array with flexible-array member Message-ID: <20200302210437.GA30285@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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: 201.166.169.19 X-Source-L: No X-Exim-ID: 1j8sBz-0004O8-4B X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.169.19]:16672 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 2 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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/net/ethernet/mellanox/mlxfw/mlxfw_mfa2.c | 2 +- drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2.c b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2.c index 79057af4fe99..5d9ddf36fb4e 100644 --- a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2.c +++ b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2.c @@ -496,7 +496,7 @@ mlxfw_mfa2_file_component_tlv_get(const struct mlxfw_mfa2_file *mfa2_file, struct mlxfw_mfa2_comp_data { struct mlxfw_mfa2_component comp; - u8 buff[0]; + u8 buff[]; }; static const struct mlxfw_mfa2_tlv_component_descriptor * diff --git a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv.h b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv.h index 33c971190bba..2014a5de5a01 100644 --- a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv.h +++ b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv.h @@ -11,7 +11,7 @@ struct mlxfw_mfa2_tlv { u8 version; u8 type; __be16 len; - u8 data[0]; + u8 data[]; } __packed; static inline const struct mlxfw_mfa2_tlv * -- 2.25.0