4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit a9f11f963a546fea9144f6a6d1a307e814a387e7 ]
Be careful when comparing tcp_time_stamp to some u32 quantity,
otherwise result can be surprising.
Fixes: 7c106d7e782b ("[TCP]: TCP Low Priority congestion control")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_lp.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -264,13 +264,15 @@ static void tcp_lp_pkts_acked(struct soc
{
struct tcp_sock *tp = tcp_sk(sk);
struct lp *lp = inet_csk_ca(sk);
+ u32 delta;
if (sample->rtt_us > 0)
tcp_lp_rtt_sample(sk, sample->rtt_us);
/* calc inference */
- if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
- lp->inference = 3 * (tcp_time_stamp - tp->rx_opt.rcv_tsecr);
+ delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+ if ((s32)delta > 0)
+ lp->inference = 3 * delta;
/* test if within inference */
if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))