tracing: Have trigger filter parsing errors show up in error_log

It is annoying that the filter parsing of triggers do not show up in the
error_log. Trying to figure out what is incorrect in the input is
difficult when it fails for a typo.

Have the errors of filter parsing show up in error_log as well.

Link: https://lore.kernel.org/linux-trace-kernel/[email protected]

Cc: Masami Hiramatsu <[email protected]>
Cc: Tom Zanussi <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: rostedt

kernel/trace/trace_events_trigger.c

@@ -1067,7 +1067,14 @@ int set_trigger_filter(char *filter_str,
 
 	/* The filter is for the 'trigger' event, not the triggered event */
 	ret = create_event_filter(file->tr, file->event_call,
-				  filter_str, false, &filter);
+				  filter_str, true, &filter);
+
+	/* Only enabled set_str for error handling */
+	if (filter) {
+		kfree(filter->filter_string);
+		filter->filter_string = NULL;
+	}
+
 	/*
 	 * If create_event_filter() fails, filter still needs to be freed.
 	 * Which the calling code will do with data->filter.