This post is about dbus daemon fails with undefined symbol and fix it.

To be honest, i was busy with this issue for 2 days. I have googled everywhere and tried all the suggested solutions, but nothing works. While the system boots, it still hanging with start D-bus messages. It takes too long to reach the console, but even with that, you will not be able to log in with LDAP or ssh Clients. All services using the Dbus are down.

The Only Way is to use Rescue mode to handle this issue quickly.

The issue is due to dbus linking against an incompatible library named libexpat.so.1 and taking precedence over the library shipped by Red Hat in /usr/lib64.

Step 1 : Investigation

Please login as root and use journalctl commands to see the Errors

journalctl --since "2 days ago" | grep -i error

journalctl --since "2 days ago" | grep -i Failed

Step 2 : Analyse

Now we know something wrong with /sur/bin/dbus-doemon

#ldd /usr/bin/dbus-daemon | grep libexpat    
libexpat.so.1 => /app/Oracle/product/12.2.0/client_1/lib/libexpat.so.1 (0x00007f6d65a89000)

Step 3 : dbus daemon fails with undefined symbol – Solution

Check and Remove the paths to 3rd party libraries from /etc/ld.so.conf.d

#cat /etc/ld.so.conf.d/temp.conf

/app/Oracle/product/12.2.0/client_1/lib/

Remove or move to other Directory

mv /etc/ld.so.conf.d/temp.conf /root

Rebuild the ld cache

#ldconfig

Verify that dbus now links against the expected library in /usr/lib64

# ldd /usr/bin/dbus-daemon | grep libexpat
        libexpat.so.1 => /lib64/libexpat.so.1 (0x00007f43abb55000)

as you see the system is back to normal

Step 4 : Reboot the server

All services should be now running and OK including the Dbus and Polikit

systemctl status polkit and Dbus

# systemctl   status   polkit
● polkit.service - Authorization Manager
   Loaded: loaded (/usr/lib/systemd/system/polkit.service; static; vendor preset: disabled)
   Active: active (running) since Fri 2022-02-18 09:31:01 CET; 4h 17min ago
     Docs: man:polkit(8)
 Main PID: 901 (polkitd)
   CGroup: /system.slice/polkit.service
           └─901 /usr/lib/polkit-1/polkitd --no-debug

systemctl   status   dbus
● dbus.service - D-Bus System Message Bus
   Loaded: loaded (/usr/lib/systemd/system/dbus.service; static; vendor preset: disabled)
   Active: active (running) since Fri 2022-02-18 09:31:01 CET; 4h 17min ago
     Docs: man:dbus-daemon(1)
 Main PID: 881 (dbus-daemon)
   CGroup: /system.slice/dbus.service
           └─881 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation

Please see also our article related to Polkit and Dus with this Error message

“Authorization not available”. Check if polkit service is running”