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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 E12AFC43387 for ; Wed, 19 Dec 2018 20:22:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3E0420866 for ; Wed, 19 Dec 2018 20:22:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729892AbeLSUWo (ORCPT ); Wed, 19 Dec 2018 15:22:44 -0500 Received: from smtprelay0016.hostedemail.com ([216.40.44.16]:37724 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728613AbeLSUWo (ORCPT ); Wed, 19 Dec 2018 15:22:44 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id B86FF45B4; Wed, 19 Dec 2018 20:22:42 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: metal68_8ba5d785e4e44 X-Filterd-Recvd-Size: 1938 Received: from XPS-9350.home (unknown [47.151.153.53]) (Authenticated sender: joe@perches.com) by omf08.hostedemail.com (Postfix) with ESMTPA; Wed, 19 Dec 2018 20:22:39 +0000 (UTC) Message-ID: Subject: Re: [PATCH 2/7] tracing: Change strlen to sizeof for hist trigger static strings From: Joe Perches To: Tom Zanussi , Steven Rostedt Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel@joelfernandes.org, mathieu.desnoyers@efficios.com, julia@ni.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Date: Wed, 19 Dec 2018 12:22:38 -0800 In-Reply-To: <1545250591.4161.2.camel@kernel.org> References: <20181219144047.49fabfa6@gandalf.local.home> <1545248809.2396.2.camel@kernel.org> <1545250591.4161.2.camel@kernel.org> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-12-19 at 14:16 -0600, Tom Zanussi wrote: > > How's this? > > [PATCH] tracing: Introduce and use strcmp_const() for hist triggers > > Provide a new strcmp_const() macro and make use of it instead of the > longer and more error-prone strncmp(str, "str", sizeof("str") - 1). [] > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c [] > @@ -22,6 +22,9 @@ > > #define STR_VAR_LEN_MAX 32 /* must be multiple of sizeof(u64) */ > > +#define strcmp_const(str, str_const) \ > + strncmp(str, str_const, sizeof(str_const) - 1) Not good as it's too easy to pass a pointer as str_const and sizeof(pointer) - 1 isn't likely the string length.