I am fully aware of OFA and I strictly follow
that. I am looking for listener.log file
in the default location which is $ORACLE_HOME/network/log.
The permissions on this *specific* directory are 777.
There is no log file in this location nor on the entire file system.
I think I found out the problem for this.
I was able to figure it out on my own.
Thanks for your attention to this issue.
Few days back, I had deleted the "listener.log"
file as it was growing big. It seems that Oracle
will not create this file back again (after you delete it)
until your STOP and START or re-start the listener process/service.
The file got created now after the listener process was stopped