diff -r 112b85020dc9 -r b26390e77237 ucx/kv_list.c
--- a/ucx/kv_list.c	Wed Nov 12 18:37:58 2025 +0100
+++ b/ucx/kv_list.c	Tue Dec 09 12:13:43 2025 +0100
@@ -98,7 +98,7 @@
 }
 
 static CxHashKey *cx_kv_list_loc_key(cx_kv_list *list, void *node_data) {
-    return (CxHashKey*)((char*)node_data + list->list.base.collection.elem_size);
+    return (CxHashKey*)((char*)node_data - list->list.loc_data + list->list.loc_extra);
 }
 
 static void cx_kvl_deallocate(struct cx_list_s *list) {
@@ -559,7 +559,7 @@
     CxList *list = cxLinkedListCreate(allocator, comparator, elem_size);
     if (list == NULL) return NULL; // LCOV_EXCL_LINE
     cx_linked_list *ll = (cx_linked_list*)list;
-    ll->extra_data_len = sizeof(CxHashKey);
+    cx_linked_list_extra_data(ll, sizeof(CxHashKey));
     CxMap *map = cxHashMapCreate(allocator, CX_STORE_POINTERS, 0);
     if (map == NULL) { // LCOV_EXCL_START
         cxListFree(list);