4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Xin Long <lucien....@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 <ji...@redhat.com> Signed-off-by: Xin Long <lucien....@gmail.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Sasha Levin <alexander.le...@verizon.com> Signed-off-by: Greg Kroah-Hartman <gre...@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;