diff --git a/src/feature/control/control_fmt.c b/src/feature/control/control_fmt.c
index 6071d82ee4..a48c89e6c7 100644
--- a/src/feature/control/control_fmt.c
+++ b/src/feature/control/control_fmt.c
@@ -167,7 +167,7 @@ circuit_describe_status_for_controller(origin_circuit_t *circ)
 
 /** Allocate and return a description of <b>conn</b>'s current status. */
 char *
-entry_connection_describe_status_for_controller(entry_connection_t *conn)
+entry_connection_describe_status_for_controller(const entry_connection_t *conn)
 {
   char *rv;
   smartlist_t *descparts = smartlist_new();
diff --git a/src/feature/control/control_fmt.h b/src/feature/control/control_fmt.h
index 84ccbab948..213df9504f 100644
--- a/src/feature/control/control_fmt.h
+++ b/src/feature/control/control_fmt.h
@@ -17,7 +17,7 @@ int write_stream_target_to_buf(entry_connection_t *conn, char *buf,
 void orconn_target_get_name(char *buf, size_t len,
                             or_connection_t *conn);
 char *circuit_describe_status_for_controller(origin_circuit_t *circ);
-char *entry_connection_describe_status_for_controller(
+char *entry_connection_describe_status_for_controller(const
                                                      entry_connection_t *conn);
 
 MOCK_DECL(const char *, node_describe_longname_by_id,(const char *id_digest));