No, that's not the concern here. KillUserProcesses is intended to reap children that were never intended to persist outside of the user session. My ssh-agent is

No, that's not the concern here. KillUserProcesses is intended to reap children that were never intended to persist outside of the user session. My ssh-agent is never going to move itself into a new scope, but it very well could have a bug that causes it to hang around after I log out. The only things that will ever create a new scope are things like tmux, screen, and maybe some variant of nohup. Here's the kinds of problems that misbehaving processes actually cause. https://bugs.freedesktop.org/show_bug.cgi?id=94508#c10 https://bugs.freedesktop.org/show_bug.cgi?id=94508#c10 And yes, KillUserProcesses reliably fixes crap like "hp-systray" from hanging your whole session in a way that isn't obvious to the user. If there's a deadlock when trying to log out, somethings gotta give otherwise your session will just persist forever.