如果 NIS/NFS 用户登录，Kubuntu 18.04 上的 X 服务器会崩溃

Question

我通过完全重新安装将一台机器更新到 Kubuntu 18.04。我们仍然使用 NFS/NIS 进行用户管理。安装了软件包，用户可以登录。我有一个本地用户dhlocal（用户 ID：1000）具有主目录，/localhome/dhlocal而用户dh（用户 ID：5000）具有主目录/home/dh。

我可以登录dhlocal到 X/KDE 会话并在那里工作，没有任何问题 - 如果只有该用户登录。

如果我登录dh，系统会暂停大约 20 秒（无论登录是在控制台还是 X 上）。然后，KDE 出现了。大约两分钟后，系统突然崩溃。.xsession-errors最后看起来像这样：

The session is not registered:  "PID 11214 does not belong to any known session"
QObject::connect: No such signal 
QDBusAbstractInterface::PrepareForSleep(bool)
powerdevil: Backend is ready, KDE Power Management system initialized
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-dh'
klauncher: Exiting on signal 15
ICE default IO error handler doing an exit(), pid = 11236, errno = 32
The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 4 (Unterbrechung während des Betriebssystemaufrufs) on X server ":0"
      after 37 requests (37 known processed) with 0 events remaining.

奇怪的是：如果我在登录到 X/KDE 的同时登录dh控制台（即Ctrl-Alt-F2并登录）dhlocal，dhlocal会话也会在两分钟后崩溃。只要我在任何控制台上登录，即使我再次登录dhlocalKDE也会发生这种情况dh。消息中.xsession-errors的dhlocal：

The X11 connection broke (error 1). Did the X11 server die?
kdeinit5: sending SIGTERM to children.
kdeinit5: Exit.
klauncher: Exiting on signal 15
The X11 connection broke (error 1). Did the X11 server die?
The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 2 (Datei oder Verzeichnis nicht gefunden) on X  server ":0"
      after 3523 requests (3523 known processed) with 0 events remaining.
klauncher: Exiting on signal 1
The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 2 (Datei oder Verzeichnis nicht gefunden) on X server ":0"
      after 1122 requests (1122 known processed) with 0 events remaining.
QProcess: Destroyed while process ("kwin_x11") is still running.
The X11 connection broke (error 1). Did the X11 server die?
Unexpected response from KInit (response = 0).
The X11 connection broke (error 1). Did the X11 server die?
startkde: Could not start ksmserver. Check your installation.
polkit-agent-helper-1: pam_authenticate failed: Authentication failure
Error: Can't open display: :0
Could not connect to D-Bus server: 
org.freedesktop.DBus.Error.NoServer: 
Failed to connect to socket /tmp/dbus-V6z3BsURMt: Verbindungsaufbau 
  abgelehnt
startkde: Shutting down...
kdeinit5_wrapper: Warning: connect(/run/user/1000/kdeinit5__0) failed: : 
No such file or directory
Error: Can not contact kdeinit5!
xprop:  unable to open display ':0'
xprop:  unable to open display ':0'
startkde: Done.

我删除了 的完整环境dh并将.profile/替换.bashrc为dhlocal的版本。我观察到两件事dh：

. 登录有 20 多秒的延迟，甚至在任何 bash 启动文件进入$HOME或/etc执行之前都会发生。我不知道这是从哪里来的。

. 出于某种原因，XDG_RUNTIME_DIR未设置为dh。但是，其他环境变量是。再次.xsession-errors为dh：

Xsession: X session started for dh at Mo 30. Apr 17:06:17 CEST 2018
localuser:dh being added to access control list
dbus-update-activation-environment: systemd --user not found, ignoring --systemd argument
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: systemd --user not found, ignoring --systemd argument
dbus-update-activation-environment: setting LANG=de_DE.UTF-8
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting PAM_KWALLET5_LOGIN=/tmp/kwallet5_dh.socket
dbus-update-activation-environment: setting MANDATORY_PATH=/usr/share/gconf/plasma.mandatory.path
dbus-update-activation-environment: setting USER=dh
dbus-update-activation-environment: setting DESKTOP_SESSION=plasma
dbus-update-activation-environment: setting DEFAULTS_PATH=/usr/share/gconf/plasma.default.path
dbus-update-activation-environment: setting PWD=/home/dh
dbus-update-activation-environment: setting HOME=/home/dh
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting XDG_SESSION_TYPE=x11
dbus-update-activation-environment: setting XDG_DATA_DIRS=/usr/share/plasma:/usr/local/share:/usr/share:/var/lib/snapd/desktop
dbus-update-activation-environment: setting XDG_SESSION_DESKTOP=KDE
dbus-update-activation-environment: setting SHELL=/bin/bash
dbus-update-activation-environment: setting XDG_SESSION_CLASS=user
dbus-update-activation-environment: setting XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
dbus-update-activation-environment: setting IM_CONFIG_PHASE=1
dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=KDE
dbus-update-activation-environment: setting GPG_AGENT_INFO=/home/dh/.gnupg/S.gpg-agent:0:1
dbus-update-activation-environment: setting SHLVL=1
dbus-update-activation-environment: setting LOGNAME=dh
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-rMq6WSod2U,guid=9e31faa7d68efa98592ebb2b5ae730ea
dbus-update-activation-environment: setting PAM_KWALLET_LOGIN=/tmp/kwallet_dh.socket
dbus-update-activation-environment: setting XAUTHORITY=/home/dh/.Xauthority
dbus-update-activation-environment: setting XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session3
dbus-update-activation-environment: setting XDG_CONFIG_DIRS=/etc/xdg/xdg-plasma:/etc/xdg:/usr/share/kubuntu-default-settings/kf5-settings
dbus-update-activation-environment: setting PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment

这里发生了什么？我怎样才能解决这个问题？是否需要进一步的信息？