Description of problem:
普通用户注销，重新窗口登陆。会出现僵尸进程：[gdm-session-wor] <defunct>。

Version-Release number of selected component (if applicable):


How reproducible:
物理机（H3C UniServer R4900 G3），必现。
vmware虚拟机，偶尔出现。

Steps to Reproduce:
1.普通用户窗口登陆
2.用户注销
3.普通用户重新窗口登陆
4.查看进程状态：ps -ef | grep defunct

Actual results:
root      169977  132618  0 15:38 ?        00:00:00 [gdm-session-wor] <defunct>

Expected results:


Additional info:
物理机：
Dec 28 15:38:23 localhost gdm[132618]: Gdm: GdmCommon: process (pid:169977, command 'gdm-session-worker [pam/gdm-launch-environment]') isn't dying after 5
seconds, now ignoring it.
Dec 28 15:38:23 localhost gdm-x-session[170002]: GLib: Source ID 2 was not found when attempting to remove it
Dec 28 15:38:23 localhost gdm-launch-environment][169977]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

vmware虚拟机：
Dec 26 21:56:32 localhost gdm[26498]: Gdm: GdmCommon: process (pid:31043, command 'gdm-session-worker [pam/gdm-launch-environment]') isn't dying after 5 seconds, now ignoring it.
Dec 26 21:56:32 localhost gdm-wayland-session[31063]: GLib: Source ID 2 was not found when attempting to remove it
Dec 26 21:56:32 localhost dbus-daemon[31395]: [session uid=1000 pid=31395] Activating via systemd: service name='org.freedesktop.impl.portal.PermissionStore' unit='xdg-permission-store.service' requested by ':1.15' (uid=1000 pid=31450 comm="/usr/bin/gnome-shell ")
Dec 26 21:56:32 localhost systemd[31356]: Starting sandboxed app permission store...
Dec 26 21:56:32 localhost gdm-launch-environment][31043]: GLib-GObject: g_object_unref: assertion 'G_IS_OBJECT (object)' failed