diff --git a/epicardium/api/common.h b/epicardium/api/common.h
index ff0c9f3abf4da6822ca89c890c3a6bb55fab7ce6..5ebb29431fa09580fe44875ee0f76f908a21180a 100644
--- a/epicardium/api/common.h
+++ b/epicardium/api/common.h
@@ -38,7 +38,7 @@ struct api_call_mem {
 	api_id_t id;
 
 	/* ID of the current interrupt */
-	api_int_id_t int_id;
+	volatile api_int_id_t int_id;
 
 	/*
 	 * Buffer for arguments/return value.  This buffer will be