5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 0d580fbd2db084a5c96ee9c00492236a279d5e0f upstream.
It appears linux-4.14 stable needs a backport of commit 88f8598d0a30 ("tcp: exit if nothing to retransmit on RTO timeout")
Since tcp_rtx_queue_empty() is not in pre 4.15 kernels, let's refactor tcp_retransmit_timer() to only use tcp_rtx_queue_head()
I will provide to stable teams the squashed patches.
Signed-off-by: Eric Dumazet edumazet@google.com Cc: Willem de Bruijn willemb@google.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Acked-by: Soheil Hassas Yeganeh soheil@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/tcp_timer.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -452,6 +452,7 @@ void tcp_retransmit_timer(struct sock *s struct net *net = sock_net(sk); struct inet_connection_sock *icsk = inet_csk(sk); struct request_sock *req; + struct sk_buff *skb;
req = rcu_dereference_protected(tp->fastopen_rsk, lockdep_sock_is_held(sk)); @@ -464,7 +465,12 @@ void tcp_retransmit_timer(struct sock *s */ return; } - if (!tp->packets_out || WARN_ON_ONCE(tcp_rtx_queue_empty(sk))) + + if (!tp->packets_out) + return; + + skb = tcp_rtx_queue_head(sk); + if (WARN_ON_ONCE(!skb)) return;
if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && @@ -496,7 +502,7 @@ void tcp_retransmit_timer(struct sock *s goto out; } tcp_enter_loss(sk); - tcp_retransmit_skb(sk, tcp_rtx_queue_head(sk), 1); + tcp_retransmit_skb(sk, skb, 1); __sk_dst_reset(sk); goto out_reset_timer; }