Bug#1008725: systemd-logind option KillUserProcesses=true kills mount.davfs of user mount units

[Andreas Feldner]

Package: systemd
Version: 250.4-1
Severity: normal

Dear Maintainer,

I activated KillUserProcesses=true for systemd-logind by creating a file 
/etc/systemd/logind.conf.d/99-killuserprocs.conf with the content below.

Some users have user session mounts configured by a unit file 
~/.config/systemd/user/home-user-some-path.mount with the content similar to below.

This leads to all stale user process being killed after logout, which
was basically the intention.

However, the user mount of type davfs also spawns a user process /sbin/mount.davfs
each. Apparently, these processes get killed as well before a proper unmount of the
user mounts. This leads to stale mount points and stale PID files requiring manual
removal by the user before the directory can be mounted again.

I would have expected that processes spawned by the mount unit file do not get killed
by the logind session but are handled with the life cycle of the mount unit.

I did not fiddle with the KillMode settin of the mount unit, because it says to be
strongly discouraged by the man page.

Yours
Andreas.

-- Content of 99-killuserprocs.conf:
[Login]
KillUserProcesses=true
KillExcludeUsers=sddm root
--

-- Content of ~/.config/systemd/user/home-user-some-path.mount:
[Unit]
Description=Nextcloud DAV mount

[Install]
WantedBy=default.target

[Mount]
What=https://some.server.example/nextcloud/remote.php/webdav/
Where=/home/user/some/path
Type=davfs
Options=noexec,nosuid,grpid,user,_netdev
KillMode=mixed
--



-- Package-specific info:

-- System Information:
Debian Release: bookworm/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.16.0-1-amd64 (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_FIRMWARE_WORKAROUND
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages systemd depends on:
ii  adduser          3.121
ii  libacl1          2.3.1-1
ii  libapparmor1     3.0.4-2
ii  libaudit1        1:3.0.7-1+b1
ii  libblkid1        2.37.3-1+b1
ii  libc6            2.33-7
ii  libcap2          1:2.44-1
ii  libcrypt1        1:4.4.27-1.1
ii  libcryptsetup12  2:2.4.3-1
ii  libfdisk1        2.37.3-1+b1
ii  libgcrypt20      1.9.4-5
ii  libgnutls30      3.7.3-4+b1
ii  libgpg-error0    1.43-3
ii  libip4tc2        1.8.7-1
ii  libkmod2         29-1
ii  liblz4-1         1.9.3-2
ii  liblzma5         5.2.5-2
ii  libmount1        2.37.3-1+b1
ii  libpam0g         1.4.0-11
ii  libseccomp2      2.5.3-2
ii  libselinux1      3.3-1+b2
ii  libsystemd0      250.4-1
ii  libzstd1         1.4.9+dfsg-1
ii  mount            2.37.3-1+b1
ii  util-linux       2.37.3-1+b1

Versions of packages systemd recommends:
ii  dbus [default-dbus-system-bus]  1.14.0-1
ii  ntp [time-daemon]               1:4.2.8p15+dfsg-1

Versions of packages systemd suggests:
ii  libfido2-1            1.10.0-1
ii  libtss2-esys-3.0.2-0  3.2.0-1
ii  libtss2-mu0           3.2.0-1
pn  libtss2-rc0           <none>
ii  policykit-1           0.105-33
pn  systemd-container     <none>

Versions of packages systemd is related to:
ii  dbus-user-session  1.14.0-1
pn  dracut             <none>
ii  initramfs-tools    0.140
ii  libnss-systemd     250.4-1
ii  libpam-systemd     250.4-1
ii  udev               250.4-1

-- no debconf information