charon-systemd fails on raspberry pi systems under ubuntu 21.10

[Sven Lütkemeier]

After upgrading to Ubuntu 21.10 from Ubuntu 21.04 my Strongswan installation fails. It seems that charon-systemd can´t be started. The problem occurs also when using a fresh install of the offical Ubuntu Server 21.10 image (from <https://ubuntu.com/download/raspberry-pi>).

The problem doesn't exist on a VM running on an AMD64 system.

I attach the output of journalctl -xeu strongswan.service (after increasing charons loglevel to 2).

Kind regards
Sven

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: charon-systemd 5.9.1-1ubuntu3.1
ProcVersionSignature: Ubuntu 5.13.0-1008.9-raspi 5.13.14
Uname: Linux 5.13.0-1008-raspi aarch64
ApportVersion: 2.20.11-0ubuntu70
Architecture: arm64
CasperMD5CheckResult: unknown
Date: Thu Oct 21 11:54:32 2021
ProcEnviron:
 SHELL=/bin/bash
 LANG=C.UTF-8
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, no user)
SourcePackage: strongswan
UpgradeStatus: Upgraded to impish on 2021-10-19 (2 days ago)

[Tobias Brunner (tobias-strongswan)]

Looks like your kernel is missing required modules (xfrm_user etc.) or they were not automatically loaded.

[Paride Legovini (paride)]

Indeed xfrm_user.ko is missing from the Impish image (ubuntu-21.10-preinstalled-server-arm64+raspi.img), while it's present in the Focal one (ubuntu-20.04.3-preinstalled-server-arm64+raspi.img). I'm adding a kernel task to this bug report.

[Sven Lütkemeier (sven-luetkemeier)]

It appears that some kernel modules required by charon/StrongSwan are no longer part of the default raspi-kernel. They are now part of a separate package "linux-modules-extra-raspi". Installing this package allowed my installation of StrongSwan to work unter Ubuntu 21.10.

I found this out by taking a look on other bug reports concerning linux-raspi, especially this one about docker:

https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1947601

[Juerg Haefliger (juergh)]

We introduced linux-modules-extra in impish and some modules moved to that new package.