From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753171AbeDFNDz (ORCPT ); Fri, 6 Apr 2018 09:03:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:59894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752656AbeDFNBO (ORCPT ); Fri, 6 Apr 2018 09:01:14 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 841732183B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Message-Id: <20180406130112.408206643@goodmis.org> User-Agent: quilt/0.63-1 Date: Fri, 06 Apr 2018 09:00:40 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Salvatore Mesoraca Subject: [for-next][PATCH 05/18] ftrace: Drop a VLA in module_exists() References: <20180406130035.400292196@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0005-ftrace-Drop-a-VLA-in-module_exists.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Salvatore Mesoraca Avoid a VLA by using a real constant expression instead of a variable. The compiler should be able to optimize the original code and avoid using an actual VLA. Anyway this change is useful because it will avoid a false positive with -Wvla, it might also help the compiler generating better code. Link: http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Link: http://lkml.kernel.org/r/1522399988-8815-1-git-send-email-s.mesoraca16@gmail.com Signed-off-by: Salvatore Mesoraca Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index eac9ce2c57a2..16bbf062018f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3902,14 +3902,13 @@ static bool module_exists(const char *module) { /* All modules have the symbol __this_module */ const char this_mod[] = "__this_module"; - const int modname_size = MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 1; - char modname[modname_size + 1]; + char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2]; unsigned long val; int n; - n = snprintf(modname, modname_size + 1, "%s:%s", module, this_mod); + n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod); - if (n > modname_size) + if (n > sizeof(modname) - 1) return false; val = module_kallsyms_lookup_name(modname); -- 2.15.1