From 1bc13903773bc9418a8f898c462eef64b7fa1d52 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 --- net/ipv4/tcp_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index a8772e11dc1c..a5960b9b6741 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1274,7 +1274,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, 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 + 0x20000)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG); return -ENOMEM; } -- 2.20.1