armhf focal guest container fails on amd64 host with Failed to enqueue loopback interface start request: Operation not supported

[Ryutaroh Matsumoto]

How to reproduce (as root) on amd64 host running Ubuntu:

apt-get install -t groovy qemu-user-static

mmdebstrap --components="main restricted universe multiverse" --variant=standard --architectures=armhf focal /var/lib/machines/armhf-focal http://ports.ubuntu.com/ubuntu-ports/

systemd-nspawn -D /var/lib/machines/armhf-focal -b

Then I get:

Spawning container armhf-focal on /var/lib/machines/armhf-focal.
Press ^] three times within 1s to kill container.
systemd 245.4-4ubuntu3 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=hybrid)
Detected virtualization systemd-nspawn.
Detected architecture arm.

Welcome to Ubuntu 20.04 LTS!

Set hostname to <armhf-focal>.
Failed to enqueue loopback interface start request: Operation not supported
Caught <SEGV>, dumped core as pid 3.
Exiting PID 1...
Container armhf-focal failed with error code 255.

This is an upstream issue reported at https://bugs.launchpad.net/qemu/+bug/1886811
Workaround patch is also available at https://bugs.launchpad.net/qemu/+bug/1886811

[Ryutaroh Matsumoto (emojifreak)]

Fix released: https://bugs.launchpad.net/qemu/+bug/1886811/comments/6