+++ /dev/null
---- a/compat/backport-4.12.c
-+++ b/compat/backport-4.12.c
-@@ -225,6 +225,7 @@ int bp_extack_genl_register_family(struc
-
- /* copy this since the family might access it directly */
- family->attrbuf = copy->family.attrbuf;
-+ family->mcgrp_offset = copy->family.mcgrp_offset;
-
- mutex_lock(&copies_mutex);
- list_add_tail(©->list, &copies_list);