Huw Davies (@huw) commented about dlls/ntdll/unix/registry.c:
SERVER_START_REQ( load_registry ) {
req->file = wine_server_obj_handle( key );
req->access = access; wine_server_add_data( req, objattr, len );
wine_server_add_data( req, unix_name, strlen(unix_name) + 1 );
The server can't safely rely on nul-terminated strings, so just pass `strlen( unix_name )` here (and add spaces either side of `unix_name`). You'll have to make a nul-terminated copy on the server-side to pass to `fopen`.