diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 37db86145c8b..24bc0769fdd6 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2466,6 +2466,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 		else if (strcmp(modifier, "usecs") == 0)
 			*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
 		else {
+			hist_err("Invalid field modifier: ", modifier);
 			field = ERR_PTR(-EINVAL);
 			goto out;
 		}
@@ -2481,6 +2482,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
 	else {
 		field = trace_find_event_field(file->event_call, field_name);
 		if (!field || !field->size) {
+			hist_err("Couldn't find field: ", field_name);
 			field = ERR_PTR(-EINVAL);
 			goto out;
 		}
@@ -2775,6 +2777,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
 		expr->fn = hist_field_plus;
 		break;
 	default:
+		ret = -EINVAL;
 		goto free;
 	}
 
@@ -4457,7 +4460,7 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
 	struct tracing_map *map = hist_data->map;
 	struct ftrace_event_field *field;
 	struct hist_field *hist_field;
-	int i, idx;
+	int i, idx = 0;
 
 	for_each_hist_field(i, hist_data) {
 		hist_field = hist_data->fields[i];
@@ -4914,6 +4917,16 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
 		seq_printf(m, "%s", field_name);
 	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
 		seq_puts(m, "common_timestamp");
+
+	if (hist_field->flags) {
+		if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
+		    !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
+			const char *flags = get_hist_field_flags(hist_field);
+
+			if (flags)
+				seq_printf(m, ".%s", flags);
+		}
+	}
 }
 
 static int event_hist_trigger_print(struct seq_file *m,
diff --git a/localversion-rt b/localversion-rt
index b72862e06be4..a68b4337d4ce 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt30
+-rt31
