Commit b6653b36 authored Jun 21, 2019 by Eric Dumazet Committed by David S. Miller Jun 21, 2019

tcp: refine memory limit test in tcp_fragment()



tcp_fragment() might be called for skbs in the write queue.

Memory limits might have been exceeded because tcp_sendmsg() only
checks limits at full skb (64KB) boundaries.

Therefore, we need to make sure tcp_fragment() wont punish applications
that might have setup very low SO_SNDBUF values.

Fixes: f070ef2a ("tcp: tcp_fragment() should apply sane memory limits")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Christoph Paasch <cpaasch@apple.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 85f9aa75

net/ipv4/tcp_output.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1296,7 +1296,8 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
		if (nsize < 0)
		nsize = 0;

		if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf)) {
		if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf &&
		tcp_queue != TCP_FRAG_IN_WRITE_QUEUE)) {
		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
		return -ENOMEM;
		}

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