PSU patching corrupted the Oracle RDBM libraries. In order to be safe, the Oracle RDBMS 12.1.0.2 software was de-installed before a freh installatuion was done.
Ensure that there are no databases using this Oracle Home.
Following the example given in Example of Running the Deinstall Command, I ran the following commands as the oracle user to deinstall the Oracle RDBMS home:
cd /opt/app/oracle/product/12.1.0/dbhome_1/deinstall ./deinstall
The output log is attached as deinstall.log.
Although the deinstall log says that files were in use, these files were owned by root. Ran the following command to remove these files and associated directories:
sudo rm -fR /opt/app/oracle/product/12.1.0/dbhome_1