| Message ID | 1406628447-21130-1-git-send-email-christoph.paasch@uclouvain.be |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Christoph Paasch <christoph.paasch@uclouvain.be> Date: Tue, 29 Jul 2014 12:07:27 +0200 > In veno we do a multiplication of the cwnd and the rtt. This > may overflow and thus their result is stored in a u64. However, we first > need to cast the cwnd so that actually 64-bit arithmetic is done. > > A first attempt at fixing 76f1017757aa0 ([TCP]: TCP Veno congestion > control) was made by 159131149c2 (tcp: Overflow bug in Vegas), but it > failed to add the required cast in tcp_veno_cong_avoid(). > > Fixes: 76f1017757aa0 ([TCP]: TCP Veno congestion control) > Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Applied and queued up for -stable. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c index 27b9825753d1..8276977d2c85 100644 --- a/net/ipv4/tcp_veno.c +++ b/net/ipv4/tcp_veno.c @@ -144,7 +144,7 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) rtt = veno->minrtt; - target_cwnd = (tp->snd_cwnd * veno->basertt); + target_cwnd = (u64)tp->snd_cwnd * veno->basertt; target_cwnd <<= V_PARAM_SHIFT; do_div(target_cwnd, rtt);
In veno we do a multiplication of the cwnd and the rtt. This may overflow and thus their result is stored in a u64. However, we first need to cast the cwnd so that actually 64-bit arithmetic is done. A first attempt at fixing 76f1017757aa0 ([TCP]: TCP Veno congestion control) was made by 159131149c2 (tcp: Overflow bug in Vegas), but it failed to add the required cast in tcp_veno_cong_avoid(). Fixes: 76f1017757aa0 ([TCP]: TCP Veno congestion control) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> --- Notes: Resubmit as requested by David. net/ipv4/tcp_veno.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)