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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: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ilpo Järvinen 2009-11-13 13:56:33 -08:00 committed by David S. Miller
parent d01032e4fd
commit d792c1006f
1 changed files with 12 additions and 7 deletions
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19
net/ipv4/tcp.c
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@ -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. */