3.13.11-ckt15 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Herbert Xu <[email protected]> [ Upstream commit 843925f33fcc293d80acf2c5c8a78adf3344d49b ] Thomas Jarosch reported IPsec TCP stalls when a PMTU event occurs. In fact the problem was completely unrelated to IPsec. The bug is also reproducible if you just disable TSO/GSO. The problem is that when the MSS goes down, existing queued packet on the TX queue that have not been transmitted yet all look like TSO packets and get treated as such. This then triggers a bug where tcp_mss_split_point tells us to generate a zero-sized packet on the TX queue. Once that happens we're screwed because the zero-sized packet can never be removed by ACKs. Fixes: 1485348d242 ("tcp: Apply device TSO segment limit earlier") Reported-by: Thomas Jarosch <[email protected]> Signed-off-by: Herbert Xu <[email protected]> Cheers, Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- net/ipv4/tcp_output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 395f909..3bff62d 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1874,7 +1874,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now))) break; - if (tso_segs == 1) { + if (tso_segs == 1 || !sk->sk_gso_max_segs) { if (unlikely(!tcp_nagle_test(tp, skb, mss_now, (tcp_skb_is_last(sk, skb) ? nonagle : TCP_NAGLE_PUSH)))) @@ -1911,7 +1911,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, } limit = mss_now; - if (tso_segs > 1 && !tcp_urg_mode(tp)) + if (tso_segs > 1 && sk->sk_gso_max_segs && !tcp_urg_mode(tp)) limit = tcp_mss_split_point(sk, skb, mss_now, min_t(unsigned int, cwnd_quota, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
