From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 112/166] lib/ts_bm.c: replace zero-length array with flexible-array member Date: Mon, 06 Apr 2020 20:10:00 -0700 Message-ID: <20200407031000.oYeSSqjYZ%akpm@linux-foundation.org> References: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:55422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726648AbgDGDKB (ORCPT ); Mon, 6 Apr 2020 23:10:01 -0400 In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, gustavo@embeddedor.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org From: "Gustavo A. R. Silva" Subject: lib/ts_bm.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/20200211205620.GA24694@embeddedor Signed-off-by: Gustavo A. R. Silva Signed-off-by: Andrew Morton --- lib/ts_bm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/ts_bm.c~lib-ts_bm-replace-zero-length-array-with-flexible-array-member +++ a/lib/ts_bm.c @@ -52,7 +52,7 @@ struct ts_bm u8 * pattern; unsigned int patlen; unsigned int bad_shift[ASIZE]; - unsigned int good_shift[0]; + unsigned int good_shift[]; }; static unsigned int bm_find(struct ts_config *conf, struct ts_state *state) _