Oracle Opatch failed with "CheckActiveFilesAndExecutables"

Environment Details:
OS: Linux Server 5.8 64bit
GRID Home Version: 11.2.0.4.0
GRID Home: /opt/oracle/product/11.2.0.4.GRD

Issue: While applying patch, the opatch failed with the below error

Following executables are active : 
/opt/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1 
UtilSession failed: Prerequisite check "CheckActiveFilesAndExecutables" failed.  

Solution:  The above mentioned file is still active or in use.

Check which process/tool is using the file and stop the process cleanly else kill the process.

you can use lsof(list open files) or fuser (identify processes using files or sockets) to identify the process using the file.

[oracle@linux01 ~]$ lsof /opt/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1
COMMAND    PID   USER  FD   TYPE DEVICE SIZE/OFF     NODE NAME
ons       2342 oracle mem    REG 253,53 53817421 21213079 /apps/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1
ons       2344 oracle mem    REG 253,53 53817421 21213079 /apps/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1


[oracle@linux01 ~]$ /sbin/fuser -cv /opt/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1
                     USER        PID ACCESS COMMAND
/opt/oracle/product/11.2.0.4.GRD/lib/libclntsh.so.11.1:
                     oracle     2342 F.ce. ons
                     oracle     2344 F.ce. ons

Once the processes are identified, stop/kill them:
[oracle@linux01 ~]$ kill -9 2342
[oracle@linux01 ~]$ kill -9 2344