diff options
| author | Yuchung Cheng <ycheng@google.com> | 2018-12-05 14:38:38 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-05 16:34:40 -0800 |
| commit | b2b7af861122a0c0f6260155c29a1b2e594cd5b5 (patch) | |
| tree | e50108978bd22380b6d831725c8998bdd2a797d7 | |
| parent | 41727549de3e7281feb174d568c6e46823db8684 (diff) | |
tcp: fix NULL ref in tail loss probe
TCP loss probe timer may fire when the retranmission queue is empty but
has a non-zero tp->packets_out counter. tcp_send_loss_probe will call
tcp_rearm_rto which triggers NULL pointer reference by fetching the
retranmission queue head in its sub-routines.
Add a more detailed warning to help catch the root cause of the inflight
accounting inconsistency.
Reported-by: Rafael Tinoco <rafael.tinoco@linaro.org>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_output.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 318690234758..5aa600900695 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2497,15 +2497,18 @@ void tcp_send_loss_probe(struct sock *sk) goto rearm_timer; } skb = skb_rb_last(&sk->tcp_rtx_queue); + if (unlikely(!skb)) { + WARN_ONCE(tp->packets_out, + "invalid inflight: %u state %u cwnd %u mss %d\n", + tp->packets_out, sk->sk_state, tp->snd_cwnd, mss); + inet_csk(sk)->icsk_pending = 0; + return; + } /* At most one outstanding TLP retransmission. */ if (tp->tlp_high_seq) goto rearm_timer; - /* Retransmit last segment. */ - if (WARN_ON(!skb)) - goto rearm_timer; - if (skb_still_in_host_queue(sk, skb)) goto rearm_timer; |