1 files changed, 29 insertions, 1 deletions

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 65b54d6a1422..483b3fd1094f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -121,6 +121,7 @@ struct hist_field {
 	struct ftrace_event_field	*field;
 	unsigned long			flags;
 	hist_field_fn_t			fn;
+	unsigned int			ref;
 	unsigned int			size;
 	unsigned int			offset;
 	unsigned int                    is_signed;
@@ -1166,6 +1167,12 @@ static struct synth_event *find_synth_event(const char *name)
 	return NULL;
 }
 
+static struct trace_event_fields synth_event_fields_array[] = {
+	{ .type = TRACE_FUNCTION_TYPE,
+	  .define_fields = synth_event_define_fields },
+	{}
+};
+
 static int register_synth_event(struct synth_event *event)
 {
 	struct trace_event_call *call = &event->call;
@@ -1187,7 +1194,7 @@ static int register_synth_event(struct synth_event *event)
 
 	INIT_LIST_HEAD(&call->class->fields);
 	call->event.funcs = &synth_event_funcs;
-	call->class->define_fields = synth_event_define_fields;
+	call->class->fields_array = synth_event_fields_array;
 
 	ret = register_trace_event(&call->event);
 	if (!ret) {
@@ -3209,8 +3216,16 @@ static int contains_operator(char *str)
 	return field_op;
 }
 
+static void get_hist_field(struct hist_field *hist_field)
+{
+	hist_field->ref++;
+}
+
 static void __destroy_hist_field(struct hist_field *hist_field)
 {
+	if (--hist_field->ref > 1)
+		return;
+
 	kfree(hist_field->var.name);
 	kfree(hist_field->name);
 	kfree(hist_field->type);
@@ -3252,6 +3267,8 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
 	if (!hist_field)
 		return NULL;
 
+	hist_field->ref = 1;
+
 	hist_field->hist_data = hist_data;
 
 	if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS)
@@ -3463,6 +3480,17 @@ static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
 {
 	unsigned long flags = HIST_FIELD_FL_VAR_REF;
 	struct hist_field *ref_field;
+	int i;
+
+	/* Check if the variable already exists */
+	for (i = 0; i < hist_data->n_var_refs; i++) {
+		ref_field = hist_data->var_refs[i];
+		if (ref_field->var.idx == var_field->var.idx &&
+		    ref_field->var.hist_data == var_field->hist_data) {
+			get_hist_field(ref_field);
+			return ref_field;
+		}
+	}
 
 	ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
 	if (ref_field) {