This is a note to let you know that I've just added the patch titled vti: do not confirm neighbor when do pmtu update to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vti-do-not-confirm-neighbor-when-do-pmtu-update.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed 01 Jan 2020 10:36:29 PM CET From: Hangbin Liu <liuhangbin@xxxxxxxxx> Date: Sun, 22 Dec 2019 10:51:14 +0800 Subject: vti: do not confirm neighbor when do pmtu update From: Hangbin Liu <liuhangbin@xxxxxxxxx> [ Upstream commit 8247a79efa2f28b44329f363272550c1738377de ] When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. Although vti and vti6 are immune to this problem because they are IFF_NOARP interfaces, as Guillaume pointed. There is still no sense to confirm neighbour here. v5: Update commit description. v4: No change. v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Reviewed-by: Guillaume Nault <gnault@xxxxxxxxxx> Acked-by: David Ahern <dsahern@xxxxxxxxx> Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/ip_vti.c | 2 +- net/ipv6/ip6_vti.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -235,7 +235,7 @@ static netdev_tx_t vti_xmit(struct sk_bu mtu = dst_mtu(dst); if (skb->len > mtu) { - skb_dst_update_pmtu(skb, mtu); + skb_dst_update_pmtu_no_confirm(skb, mtu); if (skb->protocol == htons(ETH_P_IP)) { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -483,7 +483,7 @@ vti6_xmit(struct sk_buff *skb, struct ne mtu = dst_mtu(dst); if (skb->len > mtu) { - skb_dst_update_pmtu(skb, mtu); + skb_dst_update_pmtu_no_confirm(skb, mtu); if (skb->protocol == htons(ETH_P_IPV6)) { if (mtu < IPV6_MIN_MTU) Patches currently in stable-queue which might be from liuhangbin@xxxxxxxxx are queue-4.19/sit-do-not-confirm-neighbor-when-do-pmtu-update.patch queue-4.19/net-dst-add-new-function-skb_dst_update_pmtu_no_confirm.patch queue-4.19/vti-do-not-confirm-neighbor-when-do-pmtu-update.patch queue-4.19/net-dst-do-not-confirm-neighbor-for-vxlan-and-geneve-pmtu-update.patch queue-4.19/gtp-do-not-confirm-neighbor-when-do-pmtu-update.patch queue-4.19/ip6_gre-do-not-confirm-neighbor-when-do-pmtu-update.patch queue-4.19/net-add-bool-confirm_neigh-parameter-for-dst_ops.update_pmtu.patch queue-4.19/tunnel-do-not-confirm-neighbor-when-do-pmtu-update.patch