tcp: fix __tcp_close() to only send RST when required

If the receive queue contains payload that was already
received, __tcp_close() can send an unexpected RST.

Refine the code to take tp->copied_seq into account,
as we already do in tcp recvmsg().

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20250903084720.1168904-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet
2025-09-03 08:47:18 +00:00
committed by Jakub Kicinski
parent 69777753a8
commit 5f92385309

View File

@@ -3099,8 +3099,8 @@ bool tcp_check_oom(const struct sock *sk, int shift)
void __tcp_close(struct sock *sk, long timeout)
{
bool data_was_unread = false;
struct sk_buff *skb;
int data_was_unread = 0;
int state;
WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
@@ -3119,11 +3119,12 @@ void __tcp_close(struct sock *sk, long timeout)
* reader process may not have drained the data yet!
*/
while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
u32 end_seq = TCP_SKB_CB(skb)->end_seq;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
len--;
data_was_unread += len;
end_seq--;
if (after(end_seq, tcp_sk(sk)->copied_seq))
data_was_unread = true;
__kfree_skb(skb);
}