[PATCH] trace-cmd reset: Clear all dynamic events

[PATCH] trace-cmd reset: Clear all dynamic events

[Tzvetomir Stoyanov (VMware)]

The "trace-cmd reset" command should set ftrace state to default,
including all dynamically created events. Currently only synthetic events
are deleted. The command is enhanced to delete all dynamic events, using
the new tracefs library API for dynamic events.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tracecmd/trace-record.c | 43 ++++++++++-------------------------------
 1 file changed, 10 insertions(+), 33 deletions(-)

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index b4200db1..aee3b01a 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -5221,41 +5221,18 @@ static void clear_error_log(void)
 		clear_instance_error_log(instance);
 }
 
-static void clear_all_synth_events(void)
+static void clear_all_dynamic_events(void)
 {
-	char sevent[BUFSIZ];
-	char *save = NULL;
-	char *line;
-	char *file;
-	char *buf;
-	int len;
-
-	file = tracefs_instance_get_file(NULL, "synthetic_events");
-	if (!file)
-		return;
-
-	buf = read_file(file);
-	if (!buf)
-		goto out;
-
-	sevent[0] = '!';
-
-	for (line = strtok_r(buf, "\n", &save); line; line = strtok_r(NULL, "\n", &save)) {
-		len = strlen(line);
-		if (len > BUFSIZ - 2)
-			len = BUFSIZ - 2;
-		strncpy(sevent + 1, line, len);
-		sevent[len + 1] = '\0';
-		write_file(file, sevent);
-	}
-out:
-	free(buf);
-	tracefs_put_tracing_file(file);
-
+	/* Clear event probes first, as they may be attached to other dynamic event */
+	tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_EPROBE, true);
+	tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_KPROBE |
+				     TRACEFS_DYNEVENT_KRETPROBE |
+				     TRACEFS_DYNEVENT_UPROBE |
+				     TRACEFS_DYNEVENT_URETPROBE |
+				     TRACEFS_DYNEVENT_SYNTH,
+				     true);
 }
 
-
-
 static void clear_func_filters(void)
 {
 	struct buffer_instance *instance;
@@ -5951,7 +5928,7 @@ void trace_reset(int argc, char **argv)
 	set_buffer_size();
 	clear_filters();
 	clear_triggers();
-	clear_all_synth_events();
+	clear_all_dynamic_events();
 	clear_error_log();
 	/* set clock to "local" */
 	reset_clock();
-- 
2.34.1

Re: [PATCH] trace-cmd reset: Clear all dynamic events

[Steven Rostedt]

On Fri, 14 Jan 2022 12:57:48 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> +	/* Clear event probes first, as they may be attached to other dynamic event */
> +	tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_EPROBE, true);
> +	tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_KPROBE |
> +				     TRACEFS_DYNEVENT_KRETPROBE |
> +				     TRACEFS_DYNEVENT_UPROBE |
> +				     TRACEFS_DYNEVENT_URETPROBE |
> +				     TRACEFS_DYNEVENT_SYNTH,
> +				     true);
>  }

I accepted this patch, but really, tracefs needs something to define:

	TRACEFS_DYNEVENT_ALL

as callers should not have to call out each type of dynamic event.
Especially when we are about to add new dynamic events, causing this to
break again.

Want to add that?

Thanks Tzvetomir,

-- Steve

Re: [PATCH] trace-cmd reset: Clear all dynamic events

[Tzvetomir Stoyanov]

On Sat, Feb 12, 2022 at 4:56 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 14 Jan 2022 12:57:48 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
> > +     /* Clear event probes first, as they may be attached to other dynamic event */
> > +     tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_EPROBE, true);
> > +     tracefs_dynevent_destroy_all(TRACEFS_DYNEVENT_KPROBE |
> > +                                  TRACEFS_DYNEVENT_KRETPROBE |
> > +                                  TRACEFS_DYNEVENT_UPROBE |
> > +                                  TRACEFS_DYNEVENT_URETPROBE |
> > +                                  TRACEFS_DYNEVENT_SYNTH,
> > +                                  true);
> >  }
>
> I accepted this patch, but really, tracefs needs something to define:
>
>         TRACEFS_DYNEVENT_ALL
>
> as callers should not have to call out each type of dynamic event.
> Especially when we are about to add new dynamic events, causing this to
> break again.
>
> Want to add that?
>

Sure, I'll send a patch with that.
Thanks!


> Thanks Tzvetomir,
>
> -- Steve



-- 
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center