> My patches don't touch the rb_thread_fd_select() code. =A0thread.c:2393
> is in rb_fd_copy(), not rb_thread_fd_select(), and is the following:
>
> =A0 memcpy(dst->fdset, src, size);
>
> Shouldn't that be:
>
> =A0 memcpy(dst->fdset, src->fdset, size);
>
> since r31395?

Right. Thanks for good catching.
I'll test your patch again.