DBG3("Agent create new event with name %s, loglevel type %d, \
loglevel value %d and filter %s",
- name, loglevel_type, loglevel_value, filter_expression);
+ name, loglevel_type, loglevel_value,
+ filter_expression ? filter_expression : "NULL");
if (!name) {
ERR("Failed to create agent event; no name provided.");