This bug is missing log files that will aid in diagnosing the problem.
While running an Ubuntu kernel (not a mainline or third-party kernel)
please enter the following command in a terminal window:

apport-collect 1743746

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable
to run this command, please add a comment stating that fact and change
the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the
Ubuntu Kernel Team.

** Changed in: linux (Ubuntu)
       Status: New => Incomplete

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1743746

Title:
  4.13: unable to increase MTU configuration for GRE devices

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  [Impact]
  GRE overlay networks can't carry traffic with MTU > 1500

  [Test Case]
  sudo add-apt-repository cloud-archive:pike
  sudo apt update
  sudo apt install openvswitch-switch
  sudo ovs-vsctl add-br br-tun
  sudo ovs-vsctl add-port br-tun gre0 -- set interface gre0 type=gre 
options:remote_ip=10.100.1.1

  gre_sys device will be configured with MTU 1472.

  sudo ip link set gre_sys mtu 65000

  will fail with EINVAL.

  [Regression Potential]

  [Bug Report]

  Under Linux 4.13 its not possible to configure GRE tunnel devices with
  a MTU larger than 1500; this impacts on Open vSwitch (which creates
  tunnel devices for GRE overlay networking) and the ip tools.

  The kernel will error with:

    gre_sys: Invalid MTU 65000 requested, hw max 1500

  The side effect of this is that if overlay networks are configured
  with high MTUs, the gre devices fragment the packets and networking is
  generally slow/broken.

  This is resolved as part of the upcoming 4.15 kernel under:

  
https://github.com/torvalds/linux/commit/cfddd4c33c254954927942599d299b3865743146

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1743746/+subscriptions

-- 
Mailing list: https://launchpad.net/~kernel-packages
Post to     : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help   : https://help.launchpad.net/ListHelp

Reply via email to