@@ -2186,6 +2186,42 @@ static int tcp_can_forward_retransmit(struct sock *sk)
return 1;
}
+static void print_queue(struct sock *sk, struct sk_buff *old, struct sk_buff *hole)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb, *prev;
+
+ skb = tcp_write_queue_head(sk);
+ prev = (struct sk_buff *)(&sk->sk_write_queue);
+
+ if (skb == NULL) {
+ printk("NULL head, pkts %u\n", tp->packets_out);
+ return;
+ }
+ printk("head %p tail %p sendhead %p oldhint %p now %p hole %p high %u\n",
+ tcp_write_queue_head(sk), tcp_write_queue_tail(sk),
+ tcp_send_head(sk), old, tp->retransmit_skb_hint, hole,
+ tp->retransmit_high);
+
+ while (skb) {
+ printk("skb %p (%u-%u) next %p prev %p sacked %u\n",
+ skb, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq,
+ skb->next, skb->prev, TCP_SKB_CB(skb)->sacked);
+ if (prev != skb->prev)
+ printk("Inconsistent prev\n");
+
+ if (skb == tcp_write_queue_tail(sk)) {
+ if (skb->next != (struct sk_buff *)(&sk->sk_write_queue))
+ printk("Improper next at tail\n");
+ return;
+ }
+
+ prev = skb;
+ skb = skb->next;
+ }
+ printk("Encountered unexpected NULL\n");
+}
+
/* This gets called after a retransmit timeout, and the initially
* retransmitted data is acknowledged. It tries to continue
* resending the rest of the retransmit queue, until either
@@ -2194,12 +2230,15 @@ static int tcp_can_forward_retransmit(struct sock *sk)
* based retransmit packet might feed us FACK information again.
* If so, we use it to avoid unnecessarily retransmissions.
*/
+static int caught_it = 0;
+
void tcp_xmit_retransmit_queue(struct sock *sk)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
struct sk_buff *hole = NULL;
+ struct sk_buff *old = tp->retransmit_skb_hint;
u32 last_lost;
int mib_idx;
int fwd_rexmitting = 0;
@@ -2217,6 +2256,16 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
last_lost = tp->snd_una;
}
+checknull:
+ if (skb == NULL) {
+ if (!caught_it)
+ print_queue(sk, old, hole);
+ caught_it++;
+ if (net_ratelimit())
+ printk("Errors caught so far %u\n", caught_it);
+ return;
+ }
+
tcp_for_write_queue_from(skb, sk) {
__u8 sacked = TCP_SKB_CB(skb)->sacked;
@@ -2257,7 +2306,7 @@ begin_fwd:
} else if (!(sacked & TCPCB_LOST)) {
if (hole == NULL && !(sacked & (TCPCB_SACKED_RETRANS|TCPCB_SACKED_ACKED)))
hole = skb;
- continue;
+ goto checknull;
} else {
last_lost = TCP_SKB_CB(skb)->end_seq;
@@ -2268,7 +2317,7 @@ begin_fwd:
}
if (sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))
- continue;
+ goto checknull;
if (tcp_retransmit_skb(sk, skb))
return;
@@ -2278,6 +2327,7 @@ begin_fwd:
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
inet_csk(sk)->icsk_rto,
TCP_RTO_MAX);
+ goto checknull;
}
}