diff --git a/lib/cache_mngt.c b/lib/cache_mngt.c
index 9f8a742..8ed2129 100644
--- a/lib/cache_mngt.c
+++ b/lib/cache_mngt.c
@@ -254,6 +254,9 @@ int nl_cache_mngt_register(struct nl_cache_ops *ops)
 	if (!ops->co_name || !ops->co_obj_ops)
 		return -NLE_INVAL;
 
+	/* oo_keygen() also needs oo_compare() */
+	BUG_ON (ops->co_obj_ops->oo_keygen && !ops->co_obj_ops->oo_compare);
+
 	nl_write_lock(&cache_ops_lock);
 	if (__nl_cache_ops_lookup(ops->co_name)) {
 		nl_write_unlock(&cache_ops_lock);