Module is unknown and cannot login at the console

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Environment

SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)
SUSE Linux Enterprise Server 12 Service Pack 2 (SLES 12 SP2)
SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)
SUSE Linux Enterprise Server 12

Situation

When logging into the ncurses console as root, an error is displayed "Module is unknown" and root cannot login. Other login methods seem to work, like ssh. The system log /var/log/messages shows the following:

2017-10-06T10:27:01.754068-06:00 sles12sp3 login: PAM unable to dlopen(/lib/security/pam_limits.so): /lib/security/pam_limits.so: cannot open shared object file: No such file or directory
2017-10-06T10:27:01.754981-06:00 sles12sp3 login: PAM adding faulty module: /lib/security/pam_limits.so
2017-10-06T10:27:02.761812-06:00 sles12sp3 login: pam_unix(login:session): session opened for user root by LOGIN(uid=0)

The /etc/pam.d/login file shows the following:

session required /lib/security/pam_limits.so

Resolution

Provide a correct path to the pam_limits.so module. Edit /etc/pam.d/login and change:

session required /lib/security/pam_limits.so

to this:

session required pam_limits.so

Likewise, if the module name is incorrect, like pam_limit.so instead of pam_limits.so, the same error would occur.

Cause

Invalid PAM module path.

Disclaimer

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