After logout, process owned by the logged out user keep running. If a user connects using ssh and then, without starting any programs, signs out the following processes remain running
4 S Tom 1808940 1 0 80 0 - 22440 do_epo 11:08 ? 00:00:00 /usr/lib/systemd/systemd --user 5 S Tom 1808943 1808940 0 80 0 - 75441 - 11:08 ? 00:00:00 (sd-pam) 0 S Tom 1809033 1 0 80 0 - 108596 x64_sy 11:08 ? 00:00:00 gio monitor -f /run/systemd/sessions/13496 0 S Tom 1809062 1808940 0 80 0 - 16095 do_epo 11:08 ? 00:00:00 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
This only applies to users who use ssh, when using the system console [Gnome 3 desktop] all processes own by a user stop when that user signs out. I have a number of users who use the computer for remote access and the number of these running process grows over a few weeks.
I am using CentOS Stream 8. Kernel : 4.18.0-365.el8.x86_64 #1 SMP Thu Feb 10 16:11:23 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux