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Commit d22e1537 authored by Josh Hunt's avatar Josh Hunt Committed by David S. Miller
Browse files

tcp: fix tcp fin memory accounting 



tcp_send_fin() does not account for the memory it allocates properly, so
sk_forward_alloc can be negative in cases where we've sent a FIN:

ss example output (ss -amn | grep -B1 f4294):
tcp    FIN-WAIT-1 0      1            192.168.0.1:45520         192.0.2.1:8080
	skmem:(r0,rb87380,t0,tb87380,f4294966016,w1280,o0,bl0)
Acked-by: default avatarEric Dumazet <edumazet@google.com>

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 73ba57bf

net/ipv4/tcp_output.c

+1 −5
Original line number Original line Diff line number Diff line
@@ -2773,15 +2773,11 @@ void tcp_send_fin(struct sock *sk) 
	} else {

	} else {

		/* Socket is locked, keep trying until memory is available. */

		/* Socket is locked, keep trying until memory is available. */

		for (;;) {

		for (;;) {

			skb = alloc_skb_fclone(MAX_TCP_HEADER,

			skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation);

					       sk->sk_allocation);

			if (skb)

			if (skb)

				break;

				break;

			yield();

			yield();

		}

		}



		/* Reserve space for headers and prepare control bits. */

		skb_reserve(skb, MAX_TCP_HEADER);

		/* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */

		/* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */

		tcp_init_nondata_skb(skb, tp->write_seq,

		tcp_init_nondata_skb(skb, tp->write_seq,

				     TCPHDR_ACK | TCPHDR_FIN);

				     TCPHDR_ACK | TCPHDR_FIN);