1.opatch apply error OPatch failed with error code 73

[oracle@ora_11g 14275605]$ /opt/oracle/product/db_1/OPatch/opatch apply ./
Oracle Interim Patch Installer version 11.2.0.3.0
Copyright (c) 2012, Oracle Corporation.  All rights reserved.


Oracle Home       : /opt/oracle/product/db_1
Central Inventory : /opt/oraInventory
   from           : /opt/oracle/product/db_1/oraInst.loc
OPatch version    : 11.2.0.3.0
OUI version       : 11.2.0.3.0
Log file location : /opt/oracle/product/db_1/cfgtoollogs/opatch/opatch2012-12-18_21-45-13PM_1.log

Verifying environment and performing prerequisite checks...
Prerequisite check "CheckActiveFilesAndExecutables" failed.
The details are:


Following executables are active :
/opt/oracle/product/db_1/bin/oracle
Prerequisite check "CheckActiveFilesAndExecutables" failed.
The details are:


Following executables are active :
/opt/oracle/product/db_1/lib/libclntsh.so.11.1
UtilSession failed: Prerequisite check "CheckActiveFilesAndExecutables" failed.Prerequisite check "CheckActiveFilesAndExecutables" failed.
Log file location: /opt/oracle/product/db_1/cfgtoollogs/opatch/opatch2012-12-18_21-45-13PM_1.log

OPatch failed with error code 73

Check the error message "Check Active Files And Executables" carefully, it may be that some executables use
The library file libclntsh.so.11.1 in /opt/oracle/product/db_1/lib/ directory

2. Use fuser to check
[oracle@ora_11g oinstall]$ /sbin/fuser /opt/oracle/product/db_1/lib/libclntsh.so.11.1
/opt/oracle/product/db_1/lib/libclntsh.so.11.1: 12831m

3. Check process 12831, process 12831 is sqlplus program, it should be sqlplus is using libclntsh.so.11.1 library file
[oracle@ora_11g oinstall]$ ps -ef | grep 12831
oracle 12831 6986 0 21:44 pts/3 00:00:00 sqlplus as sysdba
oracle 12832 12831 0 21:44 ?       00:00:00 oracletest01 (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
oracle 12993 9126 0 21:47 pts/1 00:00:00 grep 12831
[oracle@ora_11g oinstall]$ 

4. Kill process 12831 and check the result
[oracle@ora_11g oinstall]$ kill -9 12831 
[oracle@ora_11g oinstall]$ ps -ef | grep 12831
oracle 13013 9126 0 21:55 pts/1 00:00:00 grep 12831

5. re-execute opatch Execute successfully