ubuntu@lp1934147-b:~$ dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.51 amd64 system and service manager
ubuntu@lp1934147-b:~$ loginctl list-sessions
SESSION UID USER SEAT TTY
2 1000 ubuntu ttyS0
1 sessions listed.
ubuntu@lp1934147-b:~$ for i in {1..100}; do sudo -b -i -u ubuntu ssh localhost
-- sleep 1; done; for i in {1..20}; do echo 'Reloading...'; sudo systemctl
daemon-reload; done
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
ubuntu@lp1934147-b:~$ loginctl list-sessions
SESSION UID USER SEAT TTY
60 1000 ubuntu
103 1000 ubuntu
105 1000 ubuntu
80 1000 ubuntu
104 1000 ubuntu
2 1000 ubuntu ttyS0
100 1000 ubuntu
63 1000 ubuntu
83 1000 ubuntu
74 1000 ubuntu
95 1000 ubuntu
64 1000 ubuntu
76 1000 ubuntu
59 1000 ubuntu
14 sessions listed.
ubuntu@lp1934147-b:~$ dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.52 amd64 system and service manager
ubuntu@lp1934147-b:~$ loginctl list-sessions
SESSION UID USER SEAT TTY
2 1000 ubuntu ttyS0
1 sessions listed.
ubuntu@lp1934147-b:~$ for i in {1..100}; do sudo -b -i -u ubuntu ssh localhost
-- sleep 1; done; for i in {1..20}; do echo 'Reloading...'; sudo systemctl
daemon-reload; done
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
Reloading...
ubuntu@lp1934147-b:~$ loginctl list-sessions
SESSION UID USER SEAT TTY
2 1000 ubuntu ttyS0
1 sessions listed.
** Tags removed: verification-needed verification-needed-bionic
verification-needed-focal verification-needed-hirsute
** Tags added: verification-done verification-done-bionic
verification-done-focal verification-done-hirsute
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1934147
Title:
systemd leaks abandoned session scopes
Status in snapd:
New
Status in systemd:
New
Status in systemd package in Ubuntu:
Fix Committed
Status in systemd source package in Bionic:
Fix Committed
Status in systemd source package in Focal:
Fix Committed
Status in systemd source package in Groovy:
Won't Fix
Status in systemd source package in Hirsute:
Fix Committed
Status in systemd source package in Impish:
Fix Committed
Bug description:
[impact]
systemd may leak sessions, leaving empty cgroups around as well as
abandoned session scopes.
[test case]
on a system where the user has a ssh key that allows noninteractive
login to localhost, and also has noninteractive sudo, run:
$ for i in {1..100}; do sudo -b -i -u ubuntu ssh localhost -- sleep 1;
done; for i in {1..20}; do echo 'Reloading...'; sudo systemctl daemon-
reload; done
check the sessions to see there have been leaked sessions:
$ loginctl list-sessions
SESSION UID USER SEAT TTY
1 1000 ubuntu ttyS0
350 1000 ubuntu
351 1000 ubuntu
360 1000 ubuntu
...
to verify the sessions were leaked, clear them out with:
$ echo '' | sudo tee
/sys/fs/cgroup/unified/user.slice/user-1000.slice/session-*.scope/cgroup.events
that should result in all the leaked sessions being cleaned up.
[regression potential]
issues during systemd pid1 reexec/reload, or issues while cleaning up
sessions, including leaking sessions/cgroups
[scope]
this is needed for all releases
upstream bug linked above, and upstream PR:
https://github.com/systemd/systemd/pull/20199
[original description]
On a system that is monitored via telegraf I found many abandoned
systemd session which I believe are created by a potential race where
systemd is reloading unit files and at the same time a user is
connecting to the system via ssh or is executing the su command.
The simple reproducer
$ for i in {1..100}; do sleep 0.2; ssh localhost sudo systemctl
daemon-reload & ssh localhost sleep 1 & done
Wait > 1 second
$ jobs -p | xargs --verbose --no-run-if-empty kill -KILL
To clean out STOPPED jobs and
$ systemctl status --all 2> /dev/null | grep --before-context 3
abandoned
will produce something similar to
│ ├─ 175 su - ubuntu
│ ├─ 178 -su
│ ├─62375 systemctl status --all
│ └─62376 grep --color=auto --before-context 3 abandoned
--
● session-273.scope - Session 273 of user ubuntu
Loaded: loaded (/run/systemd/transient/session-273.scope; transient)
Transient: yes
Active: active (abandoned) since Wed 2021-06-30 13:32:03 UTC; 4min 7s ago
--
● session-274.scope - Session 274 of user ubuntu
Loaded: loaded (/run/systemd/transient/session-274.scope; transient)
Transient: yes
Active: active (abandoned) since Wed 2021-06-30 13:32:03 UTC; 4min 7s ago
--
● session-30.scope - Session 30 of user ubuntu
Loaded: loaded (/run/systemd/transient/session-30.scope; transient)
Transient: yes
Active: active (abandoned) since Wed 2021-06-30 10:05:56 UTC; 3h 30min ago
--
● session-302.scope - Session 302 of user ubuntu
Loaded: loaded (/run/systemd/transient/session-302.scope; transient)
Transient: yes
Active: active (abandoned) since Wed 2021-06-30 13:32:04 UTC; 4min 6s ago
--
│ ├─ 175 su - ubuntu
│ ├─ 178 -su
│ ├─62375 systemctl status --all
│ └─62376 grep --color=auto --before-context 3 abandoned
The system in question is running Bionic, systemd-237-3ubuntu10.48
To manage notifications about this bug go to:
https://bugs.launchpad.net/snapd/+bug/1934147/+subscriptions
--
Mailing list: https://launchpad.net/~touch-packages
Post to : touch-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~touch-packages
More help : https://help.launchpad.net/ListHelp
