tcp: fix splice() and tcp collapsing interaction (f26845b4) · Commits · 戴 / test

Under unusual circumstances, TCP collapse can split a big GRO TCP packet while its being used in a splice(socket->pipe) operation. skb_splice_bits() releases the socket lock before calling splice_to_pipe(). [ 1081.353685] WARNING: at net/ipv4/tcp.c:1330 tcp_cleanup_rbuf+0x4d/0xfc() [ 1081.371956] Hardware name: System x3690 X5 -[7148Z68]- [ 1081.391820] cleanup rbuf bug: copied AD3BCF1 seq AD370AF rcvnxt AD3CF13 To fix this problem, we must eat skbs in tcp_recv_skb(). Remove the inline keyword from tcp_recv_skb() definition since it has three call sites. Reported-by:

Christian Becker <c.becker@traviangames.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by:

Eric Dumazet <edumazet@google.com> Tested-by:

Willy Tarreau <w@1wt.eu> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -1428,12 +1428,12 @@ static void tcp_service_net_dma(struct sock *sk, bool wait)
		}
		#endif

		static inline struct sk_buff tcp_recv_skb(struct sock sk, u32 seq, u32 *off)
		static struct sk_buff tcp_recv_skb(struct sock sk, u32 seq, u32 *off)
		{
		struct sk_buff *skb;
		u32 offset;

		skb_queue_walk(&sk->sk_receive_queue, skb) {
		while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
		offset = seq - TCP_SKB_CB(skb)->seq;
		if (tcp_hdr(skb)->syn)
		offset--;
		@@ -1441,6 +1441,11 @@ static inline struct sk_buff tcp_recv_skb(struct sock sk, u32 seq, u32 *off)
		*off = offset;
		return skb;
		}
		/* This looks weird, but this can happen if TCP collapsing
		* splitted a fat GRO packet, while we released socket lock
		* in skb_splice_bits()
		*/
		sk_eat_skb(sk, skb, false);
		}
		return NULL;
		}
		@@ -1520,8 +1525,10 @@ int tcp_read_sock(struct sock sk, read_descriptor_t desc,
		tcp_rcv_space_adjust(sk);

		/* Clean up data we have read: This will do ACK frames. */
		if (copied > 0)
		if (copied > 0) {
		tcp_recv_skb(sk, seq, &offset);
		tcp_cleanup_rbuf(sk, copied);
		}
		return copied;
		}
		EXPORT_SYMBOL(tcp_read_sock);

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