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=-8.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 29C6BC2BA1A for ; Tue, 7 Apr 2020 03:10:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E2DD020716 for ; Tue, 7 Apr 2020 03:09:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="jRE8H/Lj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2DD020716 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 968BB8E0075; Mon, 6 Apr 2020 23:09:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8F1358E0062; Mon, 6 Apr 2020 23:09:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 808828E0075; Mon, 6 Apr 2020 23:09:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0167.hostedemail.com [216.40.44.167]) by kanga.kvack.org (Postfix) with ESMTP id 652B68E0062 for ; Mon, 6 Apr 2020 23:09:59 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 2E7F3180AD806 for ; Tue, 7 Apr 2020 03:09:59 +0000 (UTC) X-FDA: 76679579718.26.corn86_915d8d43a4b3f X-HE-Tag: corn86_915d8d43a4b3f X-Filterd-Recvd-Size: 2891 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:09:58 +0000 (UTC) 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 ECEA5208E4; Tue, 7 Apr 2020 03:09:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586228998; bh=sXC2B05BcaKkyAGR9pIL1DPSEfUlIUlzY1IttNWATAc=; h=Date:From:To:Subject:In-Reply-To:From; b=jRE8H/LjoC8ntj6TVRIaYI7j0lYRhZxg4qYSHZs9oaN5Gm1XJGoGucenUARJkZfau Opmh4zqLUCzdQwIfL9/voFt7taYiEFBAwZ6eEnBvVDCkSnY1fiJBTZuDkZGcSNVyrw 1gIig/wsNhTR4SUldp8iOkVWypEpOnRDNO0jUZA0= Date: Mon, 06 Apr 2020 20:09:57 -0700 From: Andrew Morton To: akpm@linux-foundation.org, gustavo@embeddedor.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 111/166] lib/bch.c: replace zero-length array with flexible-array member Message-ID: <20200407030957.6nLS5r8C3%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: "Gustavo A. R. Silva" Subject: lib/bch.c: replace zero-length array with flexible-array member 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 inadvertenly introduced[3] to the codebase from now on. 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") Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor Signed-off-by: Gustavo A. R. Silva Signed-off-by: Andrew Morton --- lib/bch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/bch.c~lib-bch-replace-zero-length-array-with-flexible-array-member +++ a/lib/bch.c @@ -102,7 +102,7 @@ */ struct gf_poly { unsigned int deg; /* polynomial degree */ - unsigned int c[0]; /* polynomial terms */ + unsigned int c[]; /* polynomial terms */ }; /* given its degree, compute a polynomial size in bytes */ _