diff --git a/runtime/include/module_database.h b/runtime/include/module_database.h
index c966ed8..8336a4e 100644
--- a/runtime/include/module_database.h
+++ b/runtime/include/module_database.h
@@ -16,11 +16,31 @@ extern int            module_database_free_offset;
 static inline int
 module_database_add(struct module *module)
 {
+	/*
+	 * Assumption: Module is added to database before being listened to
+	 * TODO: Why does this matter?
+	 */
 	assert(module->socket_descriptor == -1);
 
+	int rc;
+
+	if (module_database_free_offset >= MODULE_MAX_MODULE_COUNT) goto err_no_space;
+
 	int f = __sync_fetch_and_add(&module_database_free_offset, 1);
+	if (module_database_free_offset > MODULE_MAX_MODULE_COUNT) {
+		__sync_fetch_and_subtract(&module_database_free_offset, 1);
+		goto err_no_space;
+	}
+
+	if (module_database_free_offset == MODULE_MAX_MODULE_COUNT) goto err_no_space;
 	assert(f < MODULE_MAX_MODULE_COUNT);
 	module_database[f] = module;
 
-	return 0;
+	rc = 0;
+done:
+	return rc;
+err_no_space:
+	debuglog("Cannot add module. Database is full.\n");
+	rc = -1;
+	goto done;
 }