Centos6.5 Desktop blank after startup, login enter username password hint module is unknow

Today in the oracle10g, the environment, the configuration file after the modification, restart the server.
The result is such a problem.
Access to the system with Oracle username, the desktop is blank, can not do any operation.
Is there a problem with the Oracle user creation?
The problem persists if the root user is restarted immediately. ALT+CTRL+F2 Switch to command window

Enter the root username password.
The module is UNKONW error appears
First I suspect the password is wrong.
Then I go into single mode to reset the root password (I don't understand, I can search the mother)
The problem still seems to be the problem of passwords.
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Since I don't know the problem, I can only read the log.
And then into single mode
View Log
Tail-n 100/var/log/secure
This error was found in the log.
PAM Unable to Dlopen (/lib/security/pam_limits.so):/lib/security/pam_limits.so:cannot Open Shared object File:no such fi Le or directory

So in the/lib/security/below to see if the file is in the absence. No, sure.
Pam_limits.so configured in Oracle
Vi/etc/pam.d/login

Session required/lib/security/pam_limits.so

pam_limits.so this file system in the province should have, it is not the same Linux version of the path is not the same,

On the Internet, 64-bit systems are under/lib64/security/.
Modify Vi/etc/pam.d/login
Session required/lib64/security/pam_limits.so
Reboot system

Finally went in, the problem solved.