Patch "tracing: Fix showing function event in available_events" has been added to the 3.10-stable tree

Patch "tracing: Fix showing function event in available_events" has been added to the 3.10-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    tracing: Fix showing function event in available_events

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-fix-showing-function-event-in-available_events.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d045437a169f899dfb0f6f7ede24cc042543ced9 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 24 Feb 2016 09:04:24 -0500
Subject: tracing: Fix showing function event in available_events

From: Steven Rostedt (Red Hat) <rostedt@goodmis.org>

commit d045437a169f899dfb0f6f7ede24cc042543ced9 upstream.

The ftrace:function event is only displayed for parsing the function tracer
data. It is not used to enable function tracing, and does not include an
"enable" file in its event directory.

Originally, this event was kept separate from other events because it did
not have a ->reg parameter. But perf added a "reg" parameter for its use
which caused issues, because it made the event available to functions where
it was not compatible for.

Commit 9b63776fa3ca9 "tracing: Do not enable function event with enable"
added a TRACE_EVENT_FL_IGNORE_ENABLE flag that prevented the function event
from being enabled by normal trace events. But this commit missed keeping
the function event from being displayed by the "available_events" directory,
which is used to show what events can be enabled by set_event.

One documented way to enable all events is to:

 cat available_events > set_event

But because the function event is displayed in the available_events, this
now causes an INVALID error:

 cat: write error: Invalid argument

Reported-by: Chunyu Hu <chuhu@redhat.com>
Fixes: 9b63776fa3ca9 "tracing: Do not enable function event with enable"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/trace/trace_events.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -602,7 +602,8 @@ t_next(struct seq_file *m, void *v, loff
 		 * The ftrace subsystem is for showing formats only.
 		 * They can not be enabled or disabled via the event files.
 		 */
-		if (call->class && call->class->reg)
+		if (call->class && call->class->reg &&
+		    !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
 			return file;
 	}
 


Patches currently in stable-queue which might be from rostedt@goodmis.org are

queue-3.10/tracing-fix-showing-function-event-in-available_events.patch
queue-3.10/ring-buffer-update-read-stamp-with-first-real-commit-on-page.patch
queue-3.10/scripts-recordmcount-break-hardlinks.patch
queue-3.10/tracepoints-do-not-trace-when-cpu-is-offline.patch