From 0e2dd42ae521801c007ea97fbce93b179405eca3 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 21 Jun 2019 06:09:55 -0700 Subject: [PATCH] tcp: refine memory limit test in tcp_fragment() commit b6653b3629e5b88202be3c9abc44713973f5c4b4 upstream. 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: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by: Eric Dumazet Reported-by: Christoph Paasch Tested-by: Christoph Paasch Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman (cherry picked from commit dad3a9314ac95dedc007bc7dacacb396ea10e376) --- net/ipv4/tcp_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 147ed82b73d3..221d9b72423b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1299,7 +1299,8 @@ 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; } -- 2.17.1