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Commit a35ce624 authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent beb996c1

net/ipv4/tcp_output.c

+2 −1
Original line number Diff line number Diff line
@@ -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))