Fails with the kernel in -updates, 4.15.0-176.
Works with kernel in -proposed, 4.15.0-177.
ubuntu@bionic:~$ uname -r 4.15.0-177-generic ubuntu@bionic:~$ sudo modprobe ip6_gre ubuntu@bionic:~$ unshare -Urn true ubuntu@bionic:~$ unshare -Urn true ubuntu@bionic:~$ unshare -Urn true ubuntu@bionic:~$ dmesg | tail -2 [ 14.212867] gre: GRE over IPv4 demultiplexor driver [ 14.218947] ip6_gre: GRE over IPv6 tunneling driver ubuntu@bionic:~$
Fails with the kernel in -updates, 4.15.0-176.
Works with kernel in -proposed, 4.15.0-177.
ubuntu@bionic:~$ uname -r
4.15.0-177-generic
ubuntu@bionic:~$ sudo modprobe ip6_gre
ubuntu@bionic:~$ unshare -Urn true
ubuntu@bionic:~$ unshare -Urn true
ubuntu@bionic:~$ unshare -Urn true
ubuntu@bionic:~$ dmesg | tail -2
[ 14.212867] gre: GRE over IPv4 demultiplexor driver
[ 14.218947] ip6_gre: GRE over IPv6 tunneling driver
ubuntu@bionic:~$