Commit ffb4d6c8 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

tcp: fix overflow in __tcp_retransmit_skb()

If a TCP socket gets a large write queue, an overflow can happen
in a test in __tcp_retransmit_skb() preventing all retransmits.

The flow then stalls and resets after timeouts.


sysctl -w net.core.wmem_max=1000000000
netperf -H dest -- -s 1000000000
Signed-off-by: default avatarEric Dumazet <>
Signed-off-by: default avatarDavid S. Miller <>
parent cce94483
......@@ -2605,7 +2605,8 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
* copying overhead: fragmentation, tunneling, mangling etc.
if (atomic_read(&sk->sk_wmem_alloc) >
min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf))
min_t(u32, sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2),
return -EAGAIN;
if (skb_still_in_host_queue(sk, skb))
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