Package: systemd Version: 244-3 Severity: normal File: /usr/share/man/man5/logind.conf.5.gz
The documentation about KillUserProcesses claims that processes will be left alive after user logout when set to "no", and specifically mentions tmux as one application. This is only correct under some circumstances (apparently related to cgroups, but I'm not familiar enough with them to give good details). The observed issue is as follows: * In a fresh sid installation, start Gnome under X11 (Wayland not tested). * Alt+F2, xterm * tmux * Ensure you recognize the screen again later on * Log out * Log in back again, open xterm again * tmux attach: "no sessions" -- the session was killed In comparison, when `gnome-terminal` is used to start the tmux session, it does survive the logout. In drilling down to finding the difference at all (a process that seemed very random to me in #945540, when I failed to take the terminal program used into consideration), I noticed that the cgroups involved depended on the terminal used: With xterm (or xfce4-terminal), the process seems to be launched with cgroups pids, memory, name and "" in /user.slice/user-$UID.slice/session-$SESSION.scope, whereas a surviving tmux has its "", name and memory cgroups set to /user.slice/user-$UID.slice/user@$UID.service/gnome-terminal-server.service and the pids to /user.slice/user-$UID.slice/user@$UID.service. It seems to me that processes under session-$SESSION.scope do get reaped (whether deliberately killed by logind or somehow implicily by their cgroups going away) at logout, and only those staretd from a program that happens to switch cgroups survive. Please change logind behavior to allow for all processes spawned in a login session to survive, or if that is not possible, describe in the KillUserProcesses which processes have a chance to survive. For now, a usable workaround for me is to `systemd-run --user --scope tmux` instead of tmux, but that's a workaround nobody should need to use, especially as finding the need to do so usually involves having lost one's tmux sessions over an X server crash before. Thanks chrysn (Information down here relates to my production system where I've reproduced the steps above with i3 instead of gnome). -- System Information: Debian Release: bullseye/sid APT prefers unstable APT policy: (500, 'unstable'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 5.3.0-3-amd64 (SMP w/8 CPU cores) Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages systemd depends on: ii adduser 3.118 ii libacl1 2.2.53-5 ii libapparmor1 2.13.3-7 ii libaudit1 1:2.8.5-2+b1 ii libblkid1 2.34-0.1 ii libc6 2.29-6 ii libcap2 1:2.27-1 ii libcryptsetup12 2:2.2.2-1 ii libgcrypt20 1.8.5-3 ii libgnutls30 3.6.10-5 ii libgpg-error0 1.36-7 ii libidn2-0 2.2.0-2 ii libip4tc2 1.8.4-1 ii libkmod2 26-3 ii liblz4-1 1.9.2-2 ii liblzma5 5.2.4-1+b1 ii libmount1 2.34-0.1 ii libpam0g 1.3.1-5 ii libpcre2-8-0 10.34-7 ii libseccomp2 2.4.2-2 ii libselinux1 2.9-3+b1 ii libsystemd0 244-3 ii mount 2.34-0.1 ii util-linux 2.34-0.1 Versions of packages systemd recommends: ii dbus 1.12.16-2 Versions of packages systemd suggests: ii policykit-1 0.105-26 pn systemd-container <none> Versions of packages systemd is related to: pn dracut <none> ii initramfs-tools 0.135 ii udev 244-3 -- no debconf information
