diff -urNp a/unix/posix_thread_os_hnd.c b/unix/posix_thread_os_hnd.c
--- a/unix/posix_thread_os_hnd.c	2021-08-02 15:36:49.536860558 +0200
+++ b/unix/posix_thread_os_hnd.c	2021-08-02 15:38:48.990041616 +0200
@@ -140,8 +140,6 @@ add_fd(os_handler_t       *handler,
     fd_data->data_ready = data_ready;
     fd_data->handler = handler;
     fd_data->freed = freed;
-    sel_set_fd_write_handler(posix_sel, fd, SEL_FD_HANDLER_DISABLED);
-    sel_set_fd_except_handler(posix_sel, fd, SEL_FD_HANDLER_DISABLED);
     rv = sel_set_fd_handlers(posix_sel, fd, fd_data, fd_handler, NULL, NULL,
 			     free_fd_data);
     if (rv) {