diff --git a/include/types/protocol.h b/include/types/protocol.h
index 1d3404b..f38baeb 100644
--- a/include/types/protocol.h
+++ b/include/types/protocol.h
@@ -80,9 +80,9 @@
 	int (*pause)(struct listener *l);               /* temporarily pause this listener for a soft restart */
 	void (*add)(struct listener *l, int port);      /* add a listener for this protocol and port */
 
-	struct list listeners;				/* list of listeners using this protocol */
-	int nb_listeners;				/* number of listeners */
-	struct list list;				/* list of registered protocols */
+	struct list listeners;				/* list of listeners using this protocol (under proto_lock) */
+	int nb_listeners;				/* number of listeners (under proto_lock) */
+	struct list list;				/* list of registered protocols (under proto_lock) */
 };
 
 #define CONNECT_HAS_DATA                        0x00000001 /* There's data available to be sent */