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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 6D0C6C6778A for ; Fri, 6 Jul 2018 01:06:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14DFC24011 for ; Fri, 6 Jul 2018 01:06:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14DFC24011 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932455AbeGFBGo (ORCPT ); Thu, 5 Jul 2018 21:06:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:44890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932362AbeGFBGj (ORCPT ); Thu, 5 Jul 2018 21:06:39 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (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 46791240C0; Fri, 6 Jul 2018 01:06:39 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1fbFCo-0007IG-BW; Thu, 05 Jul 2018 21:06:38 -0400 Message-Id: <20180706010638.254195015@goodmis.org> User-Agent: quilt/0.65 Date: Thu, 05 Jul 2018 21:06:06 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , Dan Carpenter Subject: [PATCH 2/6] tracing: Make create_filter() code match the comments MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" The comment in create_filter() states that the passed in filter pointer (filterp) will either be NULL or contain an error message stating why the filter failed. But it also expects the filter pointer to point to NULL when passed in. If it is not, the function create_filter_start() will warn and return an error message without updating the filter pointer. This is not what the comment states. As we always expect the pointer to point to NULL, if it is not, trigger a WARN_ON(), set it to NULL, and then continue the path as the rest will work as the comment states. Also update the comment to state it must point to NULL. Reported-by: Dan Carpenter Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_filter.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 0dceb77d1d42..893a206bcba4 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1701,6 +1701,7 @@ static void create_filter_finish(struct filter_parse_error *pe) * @filter_str: filter string * @set_str: remember @filter_str and enable detailed error in filter * @filterp: out param for created filter (always updated on return) + * Must be a pointer that references a NULL pointer. * * Creates a filter for @call with @filter_str. If @set_str is %true, * @filter_str is copied and recorded in the new filter. @@ -1718,6 +1719,10 @@ static int create_filter(struct trace_event_call *call, struct filter_parse_error *pe = NULL; int err; + /* filterp must point to NULL */ + if (WARN_ON(*filterp)) + *filterp = NULL; + err = create_filter_start(filter_string, set_str, &pe, filterp); if (err) return err; -- 2.17.1