我全新安装了 ubuntu 18.04.1。journalctl -b -p err在终端中运行，我得到：
jim@jim-Z1-7623:~$ journalctl -b -p err
-- Logs begin at Wed 2018-10-10 05:02:41 CDT, end at Mon 2018-10-15 04:23:44 CDT. --
Oct 15 04:07:18 jim-Z1-7623 lightdm[901]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shar
Oct 15 04:07:18 jim-Z1-7623 lightdm[901]: PAM adding faulty module: pam_kwallet.so
Oct 15 04:07:18 jim-Z1-7623 lightdm[901]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open sh
Oct 15 04:07:18 jim-Z1-7623 lightdm[901]: PAM adding faulty module: pam_kwallet5.so
Oct 15 04:07:19 jim-Z1-7623 wpa_supplicant[741]: dbus: wpa_dbus_get_object_properties: failed to get object properties: (none)
Oct 15 04:07:19 jim-Z1-7623 wpa_supplicant[741]: dbus: Failed to construct signal
Oct 15 04:07:20 jim-Z1-7623 lightdm[988]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shar
Oct 15 04:07:20 jim-Z1-7623 lightdm[988]: PAM adding faulty module: pam_kwallet.so
Oct 15 04:07:20 jim-Z1-7623 lightdm[988]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open sh
Oct 15 04:07:20 jim-Z1-7623 lightdm[988]: PAM adding faulty module: pam_kwallet5.so
Oct 15 04:07:31 jim-Z1-7623 NetworkManager[748]: <error> [1539594451.1039] wifi-wext: (wlx08863b9276e2): error setting powersa
Oct 15 04:07:31 jim-Z1-7623 wpa_supplicant[741]: bgscan simple: Failed to enable signal strength monitoring
Oct 15 04:07:31 jim-Z1-7623 systemd[1]: Failed to start Postfix Mail Transport Agent (instance -).
Oct 15 04:07:34 jim-Z1-7623 spice-vdagent[1332]: Cannot access vdagent virtio channel /dev/virtio-ports/com.redhat.spice.0
Oct 15 04:07:39 jim-Z1-7623 pulseaudio[1470]: [pulseaudio] pid.c: Daemon already running.
Oct 15 04:08:00 jim-Z1-7623 pulseaudio[1416]: [pulseaudio] bluez5-util.c: GetManagedObjects() failed: org.freedesktop.DBus.Err
似乎 lightdm 正在寻找 libpam-kwallet，但默认情况下未安装它。我需要安装哪些文件来纠正此错误？
谢谢，