diff --git a/utils/apparmor/aa.py b/utils/apparmor/aa.py
index 71d7ea795..74a0ec4bf 100644
--- a/utils/apparmor/aa.py
+++ b/utils/apparmor/aa.py
@@ -1696,7 +1696,7 @@ def collapse_log(hashlog, ignore_null_profiles=True):
                                         elif access == 'eavesdrop':
                                             dbus_event = DbusRule(access, bus, DbusRule.ALL, DbusRule.ALL, DbusRule.ALL, DbusRule.ALL, DbusRule.ALL, DbusRule.ALL, log_event=True)
                                         else:
-                                            raise AppArmorBug('unexpected dbus access: %s')
+                                            raise AppArmorBug('unexpected dbus access: {}'.format(access))
 
                                         if not hat_exists or not is_known_rule(aa[profile][hat], 'dbus', dbus_event):
                                             log_dict[aamode][full_profile]['dbus'].add(dbus_event)