Comment 0 for bug 2037667

We noticed that some of Netplan's integration tests started to fail on Jammy. These tests will try to create ip6gre and vti6 virtual interfaces and systemd-networkd is failing to create them starting on kernel 5.15.0-83.92. As far as I can tell, kernel 5.15.0-82.91 is the last revision where it works. So, some change between 5.15.0-82.91 and 5.15.0-83.92 is causing this regression.

How to reproduce the issue:

# Launch a jammy cloud VM:

lxc launch images:ubuntu/jammy/cloud jammy --vm
lxc shell jammy

# Create a netplan file that creates 2 tunnels:

cat > /etc/netplan/10-tun.yaml <<EOF
network:
  renderer: networkd
  version: 2
  tunnels:
    tun0:
      mode: ip6gre
      local: fe80::1
      remote: 2001:dead:beef::2
    tun1:
      mode: vti6
      local: fe80::2
      remote: 2001:dead:beef::3
EOF

# Apply the configuration

netplan apply

# Check with "ip link" that both tun0 and tun1 *were not created* and check networkd for errors:

journalctl -u systemd-networkd

Sep 28 17:04:40 jammy systemd-networkd[360]: tun0: netdev could not be created: Invalid argument
Sep 28 17:04:40 jammy systemd-networkd[360]: tun1: netdev could not be created: Invalid argument

# Download, install and boot on kernel 5.15.0-82.91

wget http://ie.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed/linux-image-5.15.0-82-generic_5.15.0-82.91_amd64.deb http://ie.archive.ubuntu.com/ubuntu/pool/main/l/linux/linux-modules-5.15.0-82-generic_5.15.0-82.91_amd64.deb

dpkg -i *.deb

grub-reboot '1>2' && reboot

# Check with "ip link" again that both tun0 and tun1 were created

# Reboot again to go back to the most recent kernel and check with "ip link" that both tun0 and tun1 were not created.