diff --git a/include/linux/surface_aggregator/controller.h b/include/linux/surface_aggregator/controller.h
index cb7980805920..5b67f0f47d80 100644
--- a/include/linux/surface_aggregator/controller.h
+++ b/include/linux/surface_aggregator/controller.h
@@ -44,7 +44,7 @@ struct ssam_event {
 	u8 command_id;
 	u8 instance_id;
 	u16 length;
-	u8 data[];
+	u8 data[] __counted_by(length);
 };
 
 /**