tcp: fix overflow in __tcp_retransmit_skb()

[ Upstream commit ffb4d6c8508657824bcef68a36b2a0f9d8c09d10 ]

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.

Tested:

sysctl -w net.core.wmem_max=1000000000
netperf -H dest -- -s 1000000000

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Dumazet 2016-09-15 08:12:33 -07:00 committed by Greg Kroah-Hartman
parent beb996c1c3
commit a35ce624a3

View file

@ -2569,7 +2569,8 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
* 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),
sk->sk_sndbuf))
return -EAGAIN;
if (skb_still_in_host_queue(sk, skb))