Prerequisite check "CheckActiveFilesAndExecutables" failed while applying opatch

Problem description:

applying opatch failled:

$ /u01/app/crs/11.2.0.2/OPatch/opatch napply -oh /u01/app/oracle/product/11.2.0.2/db_2 -local /dba/staging/patches/16056267/
Oracle Interim Patch Installer version 11.2.0.3.4
Copyright (c) 2012, Oracle Corporation.  All rights reserved.


Oracle Home       : /u01/app/oracle/product/11.2.0.2/db_2
Central Inventory : /u01/app/oraInventory
   from           : /u01/app/oracle/product/11.2.0.2/db_2/oraInst.loc
OPatch version    : 11.2.0.3.4
OUI version       : 11.2.0.2.0
Log file location : /u01/app/oracle/product/11.2.0.2/db_2/cfgtoollogs/opatch/opatch2013-05-16_12-23-56PM_1.log

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


Following executables are active :
/u01/app/oracle/product/11.2.0.2/db_2/lib/libclntsh.so.11.1
UtilSession failed: Prerequisite check "CheckActiveFilesAndExecutables" failed.
Log file location: /u01/app/oracle/product/11.2.0.2/db_2/cfgtoollogs/opatch/opatch2013-05-16_12-23-56PM_1.log

OPatch failed with error code 73

Cause of problem:

Something is using oracle library.

Solution of problem:

Using fuser to find which process is using that library and kill it.

/sbin/fuser /u01/app/oracle/product/11.2.0.2/db_2/lib/libclntsh.so.11.1
/u01/app/oracle/product/11.2.0/db_2/lib/libclntsh.so.11.1: 12195m

ps -ef|grep 12195
kill -9 12195