Aaaand the upstream has decided they can't/won't fix this issue. One thing that bothers me about this whole situation is that, in order for background services like this one to be cleaned up after logout, they need to behave "correctly." From my point of view, this is backwards.
When the system is preparing to reboot, it first sends SIGTERM to all user processes, waits a few seconds, and then sends SIGKILL. Processes that behave correctly are allowed to close down cleanly, and those that don't, are terminated forcibly. If you didn't have that SIGKILL part, then one badly-behaving process could delay the reboot indefinitely. By doing things this way, good behavior is rewarded, but not required. Something like that should be the case for user sessions, although there are exceptions (screen, tmux, nohup), and SIGKILL might be excessive. The upstream bug mentioned a few other processes that remained visible under session-status, and I myself have seen similar behavior from at- spi2-core (haven't determined yet if a bug report is in order for that one). We're going to be fighting a losing battle if every single desktop background service in Ubuntu has to do things correctly in order to avoid keeping the session open after logout. There needs to be a failsafe of some kind. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1877528 Title: Applet does not terminate at end of X desktop session Status in System Config Printer: New Status in lightdm package in Ubuntu: New Status in sddm package in Ubuntu: New Status in system-config-printer package in Ubuntu: Triaged Status in systemd package in Ubuntu: Invalid Status in system-config-printer package in Debian: Unknown Bug description: This concerns system-config-printer 1.5.12-0ubuntu1 in Ubuntu focal. I log into the Xfce desktop, and then logout. The screen returns to the LightDM login screen. A few minutes later, "loginctl list-sessions" shows the following: SESSION UID USER SEAT TTY 9 0 root c2 1000 skunk seat0 c3 116 lightdm seat0 3 sessions listed. Output from "loginctl session-status c2": c2 - skunk (1000) Since: Fri 2020-05-08 03:09:05 EDT; 9min ago Leader: 2530 Seat: seat0; vc7 Display: :0 Service: lightdm; type x11; class user Desktop: xubuntu State: closing Unit: session-c2.scope └─2856 /usr/bin/python3 /usr/share/system-config-printer/applet.py This process sticks around forever until I kill it, or its parent "systemd --user" process. Only then does the session disappear from list-sessions. When I run "session-status" while I'm logged in, I see a list of nearly 30 desktop-related processes. All of them except this one go away on logout. This one should too. To manage notifications about this bug go to: https://bugs.launchpad.net/system-config-printer/+bug/1877528/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
