Commit 843925f33fcc293d80acf2c5c8a78adf3344d49b
Committed by
David S. Miller
David S. Miller
1 parent
c484994eb3
Exists in
ti-lsk-linux-4.1.y
and in
10 other branches
tcp: Do not apply TSO segment limit to non-TSO packets
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 <thomas.jarosch@intra2net.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cheers, Signed-off-by: David S. Miller <davem@davemloft.net>
Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff
net/ipv4/tcp_output.c
| ... | ... | @@ -2019,7 +2019,7 @@ |
| 2019 | 2019 | if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now))) |
| 2020 | 2020 | break; |
| 2021 | 2021 | |
| 2022 | - if (tso_segs == 1) { | |
| 2022 | + if (tso_segs == 1 || !max_segs) { | |
| 2023 | 2023 | if (unlikely(!tcp_nagle_test(tp, skb, mss_now, |
| 2024 | 2024 | (tcp_skb_is_last(sk, skb) ? |
| 2025 | 2025 | nonagle : TCP_NAGLE_PUSH)))) |
| ... | ... | @@ -2032,7 +2032,7 @@ |
| 2032 | 2032 | } |
| 2033 | 2033 | |
| 2034 | 2034 | limit = mss_now; |
| 2035 | - if (tso_segs > 1 && !tcp_urg_mode(tp)) | |
| 2035 | + if (tso_segs > 1 && max_segs && !tcp_urg_mode(tp)) | |
| 2036 | 2036 | limit = tcp_mss_split_point(sk, skb, mss_now, |
| 2037 | 2037 | min_t(unsigned int, |
| 2038 | 2038 | cwnd_quota, |
