This is a note to let you know that I've just added the patch titled

ip_gre: remove the incorrect mtu limit for ipgre tap

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ip_gre-remove-the-incorrect-mtu-limit-for-ipgre-tap.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Feb 28 16:23:28 CET 2018

From: Xin Long lucien.xin@gmail.com Date: Mon, 18 Dec 2017 14:24:35 +0800 Subject: ip_gre: remove the incorrect mtu limit for ipgre tap

From: Xin Long lucien.xin@gmail.com

[ Upstream commit cfddd4c33c254954927942599d299b3865743146 ]

ipgre tap driver calls ether_setup(), after commit 61e84623ace3 ("net: centralize net_device min/max MTU checking"), the range of mtu is [min_mtu, max_mtu], which is [68, 1500] by default.

It causes the dev mtu of the ipgre tap device to not be greater than 1500, this limit value is not correct for ipgre tap device.

Besides, it's .change_mtu already does the right check. So this patch is just to set max_mtu as 0, and leave the check to it's .change_mtu.

Fixes: 61e84623ace3 ("net: centralize net_device min/max MTU checking") Reported-by: Jianlin Shi jishi@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/ip_gre.c | 1 + 1 file changed, 1 insertion(+)

--- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1274,6 +1274,7 @@ static const struct net_device_ops erspa static void ipgre_tap_setup(struct net_device *dev) { ether_setup(dev); + dev->max_mtu = 0; dev->netdev_ops = &gre_tap_netdev_ops; dev->priv_flags &= ~IFF_TX_SKB_SHARING; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.14/ip_gre-remove-the-incorrect-mtu-limit-for-ipgre-tap.patch queue-4.14/ip6_gre-remove-the-incorrect-mtu-limit-for-ipgre-tap.patch queue-4.14/ip6_tunnel-allow-ip6gre-dev-mtu-to-be-set-below-1280.patch queue-4.14/vxlan-update-skb-dst-pmtu-on-tx-path.patch queue-4.14/ip6_tunnel-get-the-min-mtu-properly-in-ip6_tnl_xmit.patch queue-4.14/sctp-fix-the-issue-that-a-__u16-variable-may-overflow-in-sctp_ulpq_renege.patch