Bug#992990: systemd: Does not clean up user session

[Samuel Thibault]

Package: systemd
Version: 247.3-6
Severity: normal

Hello,

It seems that the user sessions are not getting cleaned up when it
crashes unexpectedly, and notably the dbus session bus, which can lead
to various oddities. To reproduce:

- logging in from lightdm ($USER is ff)
- the MATE desktop starts
- the attached snapshot shows the dbus-daemon running: not only the ones
  for the ff user, but also for lightdm (!?)
- as root in a mate-terminal, run systemctl restart lightdm
- the MATE session thus gets completely interrupted, lightdm shows up
  again
- logging in again as $USER ff
- the MATE desktop starts
- the attached snapshot shows that it's still the same dbus-daemon
  running: again not only the ones for the ff user, but also for lightdm

These surviging processes are worrying: when a user is not connected,
should there really be such remainings?  I understand that a user may be
running e.g. screen sessions, but more than this?

I could check that systemd 249.3-3 from experimental behaves the same

Samuel

-- Package-specific info:

-- System Information:
Debian Release: 11.0
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable-debug'), (500, 'testing-debug'), (500, 'stable-debug'), (500, 'proposed-updates-debug'), (500, 'proposed-updates'), (500, 'oldstable-proposed-updates-debug'), (500, 'oldstable-proposed-updates'), (500, 'oldoldstable'), (500, 'buildd-unstable'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental-debug'), (1, 'buildd-experimental'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.13.0 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages systemd depends on:
ii  adduser            3.118
ii  libacl1            2.2.53-10
ii  libapparmor1       2.13.6-10
ii  libaudit1          1:3.0.5-1
ii  libblkid1          2.36.1-8
ii  libc6              2.31-13
ii  libcap2            1:2.44-1
ii  libcrypt1          1:4.4.18-4
ii  libcryptsetup12    2:2.3.5-1
ii  libgcrypt20        1.8.7-6
ii  libgnutls30        3.7.1-5
ii  libgpg-error0      1.38-2
ii  libip4tc2          1.8.7-1
ii  libkmod2           28-1
ii  liblz4-1           1.9.3-2
ii  liblzma5           5.2.5-2
ii  libmount1          2.36.1-8
ii  libpam0g           1.4.0-9
ii  libseccomp2        2.5.1-1
ii  libselinux1        3.1-3
ii  libsystemd0        247.9-1
ii  libzstd1           1.4.8+dfsg-2.1
ii  mount              2.36.1-8
ii  ntp [time-daemon]  1:4.2.8p15+dfsg-1
ii  util-linux         2.36.1-8

Versions of packages systemd recommends:
ii  dbus  1.13.18-1

Versions of packages systemd suggests:
ii  policykit-1        0.105-31
pn  systemd-container  <none>

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.140
ii  libnss-systemd   247.9-1
ii  libpam-systemd   247.9-1
ii  udev             247.9-1

-- Configuration Files:
/etc/systemd/journald.conf changed [not included]
/etc/systemd/logind.conf changed [not included]

-- no debconf information

-- 
Samuel
#include <culture.h>
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