Su root, incorrect password, the password is correct

CentOS system, when using SU prompts: incorrect password, but the password is indeed correct.

Looked for a long time, using the following methods:

A. View
/ETC/PAM.D/SU file See if the following sentence is set to work.
Auth Required pam_whell.so Use_uid

Was looking at
/etc/login.defs file is not the following sentence
Su_wheel_only Yes

If it is, comment out the.

Two. Look at the/bin/su file's property is ' rwsr-xr-x ', if not please mend.

chmod u+s/bin/su

if U-any other user can, a particular user does not, the solution is:

Note the UID and GID of the user and the associated group, delete, rebuild, give the same GID and group ID

Note: No, delete the user, recreate, add group

Method Source: http://topic.csdn.net/u/20100115/10/c57ea30c-f38b-42ba-8aa9-23e7c92efb35.html