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Commit d792c100 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: provide more information on the tcp receive_queue bugs 



The addition of rcv_nxt allows to discern whether the skb
was out of place or tp->copied. Also catch fancy combination
of flags if necessary (sadly we might miss the actual causer
flags as it might have already returned).

Btw, we perhaps would want to forward copied_seq in
somewhere or otherwise we might have some nice loop with
WARN stuff within but where to do that safely I don't
know at this stage until more is known (but it is not
made significantly worse by this patch).

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d01032e4

net/ipv4/tcp.c

+12 −7
Original line number Diff line number Diff line
@@ -1183,7 +1183,9 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) 
#if TCP_DEBUG

	struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);



	WARN_ON(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq));

	WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),

	     KERN_INFO "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",

	     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);

#endif



	if (inet_csk_ack_scheduled(sk)) {
@@ -1430,11 +1432,13 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
			/* Now that we have two receive queues this

			 * shouldn't happen.

			 */

			if (before(*seq, TCP_SKB_CB(skb)->seq)) {

				printk(KERN_INFO "recvmsg bug: copied %X "

				       "seq %X\n", *seq, TCP_SKB_CB(skb)->seq);

			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),

			     KERN_INFO "recvmsg bug: copied %X "

				       "seq %X rcvnxt %X fl %X\n", *seq,

				       TCP_SKB_CB(skb)->seq, tp->rcv_nxt,

				       flags))

				break;

			}



			offset = *seq - TCP_SKB_CB(skb)->seq;

			if (tcp_hdr(skb)->syn)

				offset--;
@@ -1443,8 +1447,9 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
			if (tcp_hdr(skb)->fin)

				goto found_fin_ok;

			WARN(!(flags & MSG_PEEK), KERN_INFO "recvmsg bug 2: "

					"copied %X seq %X\n", *seq,

					TCP_SKB_CB(skb)->seq);

					"copied %X seq %X rcvnxt %X fl %X\n",

					*seq, TCP_SKB_CB(skb)->seq,

					tp->rcv_nxt, flags);

		}



		/* Well, if we have backlog, try to process it now yet. */