Report.get_logind_session fails to determine session on cgroup2 systems

[Benjamin Drung]

Ubuntu >= 22.04 uses only cgroup2 (Ubuntu 20.04 used both and Ubuntu 18.04 only cgroup version 1). Report.get_logind_session will fail to determine the logind session and always return None if only cgroup2 is used.

get_logind_session searches for cgroup lines with "name=systemd:" and then extracts the session from "/session-". This worked in Ubuntu 16.04 but started failing in 18.04.

Content of /proc/self/cgroup when printed from a terminal inside a Ubuntu desktop session:

Ubuntu 16.04 (xenial)
---------------------

```
12:cpuset:/
11:perf_event:/
10:pids:/user.slice/user-1000.slice
9:blkio:/
8:hugetlb:/
7:net_cls,net_prio:/
6:cpu,cpuacct:/
5:devices:/user.slice
4:freezer:/
3:rdma:/
2:memory:/
1:name=systemd:/user.slice/user-1000.slice/session-c1.scope
```

Ubuntu 18.04 (bionic)
---------------------

```
12:freezer:/
11:net_cls,net_prio:/
10:memory:/
9:rdma:/
8:cpu,cpuacct:/
7:devices:/user.slice
6:perf_event:/
5:cpuset:/
4:pids:/user.slice/user-1000.slice/[e-mail]
3:hugetlb:/
2:blkio:/
1:name=systemd:/user.slice/user-1000.slice/[e-mail]/gnome-terminal-server.service
0::/user.slice/user-1000.slice/[e-mail]/gnome-terminal-server.service
```

Ubuntu 20.04 (focal)
---------------------

```
13:memory:/user.slice/user-1000.slice/[e-mail]
12:perf_event:/
11:misc:/
10:pids:/user.slice/user-1000.slice/[e-mail]
9:hugetlb:/
8:cpuset:/
7:blkio:/
6:devices:/user.slice
5:cpu,cpuacct:/
4:freezer:/
3:rdma:/
2:net_cls,net_prio:/
1:name=systemd:/user.slice/user-1000.slice/[e-mail]/apps.slice/apps-org.gnome.Terminal.slice/vte-spawn-ad936f4d-0d62-4ac4-bbd8-0e766d8a3b1f.scope
0::/user.slice/user-1000.slice/[e-mail]/apps.slice/apps-org.gnome.Terminal.slice/vte-spawn-ad936f4d-0d62-4ac4-bbd8-0e766d8a3b1f.scope
```

Ubuntu 22.04 (jammy)
---------------------

```
0::/user.slice/user-1000.slice/[e-mail]/app.slice/app-org.gnome.Terminal.slice/vte-spawn-0c3f8b02-b112-4cab-accc-764cbb223bac.scope
```

[Benjamin Drung (bdrung)]

I checked the bug reports against apport between 2018 and now, but I found none complaining about this regression. If no one objects (and provides a way to determine the current session and the session of a process), I will remove that code.

[Benjamin Drung (bdrung)]

Remove skipping crashes that happened during logout: https://github.com/canonical/apport/pull/278

[Benjamin Drung (bdrung)]

https://github.com/canonical/apport/pull/278 got merged.

[Launchpad Janitor (janitor)]

This bug was fixed in the package apport - 2.28.0-0ubuntu1

---------------
apport (2.28.0-0ubuntu1) noble; urgency=medium

  * New upstream release
    - ui: remove skipping crashes that happened during logout (LP: #2043393)
    - setup: set minimum Java release to 8 (LP: #2045705)
    - support systemd-coredump as core dump handler (LP: #2048136)
  * Drop patches that were applied upstream
  * Address pylint complaints in patches and package hooks
  * Replace build dependency pkg-config by pkgconf
  * Suggest python3-zstandard in python3-problem-report for read support

 -- Benjamin Drung <email address hidden> Thu, 22 Feb 2024 15:20:00 +0100