Comment 91 for bug 1711407

> is it possibility that sk->sk_dst_cache is overwritten?

maybe ;-)

> like in __sk_dst_check,
> when tcp timer tries to resend a packet, at the same time, tcp_close is called

tcp_close() locks the sock; tcp_retransmit_timer() is also called with the sock locked. So they should not be operating on the same sock concurrently.