From: Eric Dumazet Date: Thu, 15 Sep 2016 15:12:33 +0000 (-0700) Subject: tcp: fix overflow in __tcp_retransmit_skb() X-Git-Tag: firefly_0821_release~176^2~4^2~17^2~35 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a35ce624a3ae06894db065727d33c17aff5cdaec;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 660c967ba84a..2902adf018b4 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -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))