From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932737AbcECCms (ORCPT ); Mon, 2 May 2016 22:42:48 -0400 Received: from smtprelay0182.hostedemail.com ([216.40.44.182]:33073 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932239AbcECCmr (ORCPT ); Mon, 2 May 2016 22:42:47 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2693:3138:3139:3140:3141:3142:3353:3622:3865:3866:3867:3868:3871:3873:3874:5007:6261:7875:7903:8660:10004:10400:10848:10967:11026:11232:11473:11658:11914:12043:12438:12517:12519:12555:12663:12740:13019:13069:13138:13148:13230:13231:13255:13311:13357:13439:13972:14096:14097:14181:14659:14721:21080:30045:30054:30070:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: sand98_35331d5bb2b31 X-Filterd-Recvd-Size: 2806 Date: Mon, 2 May 2016 22:42:44 -0400 From: Steven Rostedt To: Chunyu Hu Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Don't display trigger file for events that don't have register func Message-ID: <20160502224244.1b17428c@grimm.local.home> In-Reply-To: <1462198454-17342-1-git-send-email-chuhu@redhat.com> References: <1462198454-17342-1-git-send-email-chuhu@redhat.com> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2 May 2016 22:14:14 +0800 Chunyu Hu wrote: > Currently register function of the event will be called > through the 'reg' field of event class directly without > any check when seting up triggers. > > Triggers for events that don't support register through > debug fs (events under events/ftrace are for perf to Actually, they were created for trace-cmd. I'm not even sure if perf uses the ftrace event formats. > read event format, and most of them don't have regisgter > function except events/ftrace/function.) can't be enabled > at all, and an oops will be hit when setting up trigger > for those events, so just not showing them is an easy way > to avoid the oops. > > Signed-off-by: Chunyu Hu > --- > kernel/trace/trace_events.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index da1eeb6..9fb99fd 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -2138,9 +2138,10 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) > trace_create_file("filter", 0644, file->dir, file, > &ftrace_event_filter_fops); > > - trace_create_file("trigger", 0644, file->dir, file, > - &event_trigger_fops); > - > + if (call->class->reg) { > + trace_create_file("trigger", 0644, file->dir, file, > + &event_trigger_fops); > + } As you stated, reg is there for function tracing, and is not a good value to use as a check. Use the following check instead: if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) trace_create_file("trigger", 0644, file->dir, file, &event_trigger_fops); And add a comment that states that only event directories that can be enabled should have triggers. -- Steve > #ifdef CONFIG_HIST_TRIGGERS > trace_create_file("hist", 0444, file->dir, file, > &event_hist_fops);