Error su: Module is unknown

[sanketphadke]

When try to su to root account from normal user(having root privileges), it prompts error "su: Module is unknown" after entering password.

I checked /var/logs/secure logs showing message
su: PAM unable to resolve symbol: pam_sm_acct_mgmt

[jlehtone]

yum provides */pam_sm_acct_mgmt\* tells that package pam-devel has a man page for that.

man pam_sm_acct_mgmt then reveals that:

The pam_sm_acct_mgmt function is the service module's implementation of the pam_acct_mgmt(3) interface.

The package pam-devel is merely headers, etc that is used to build binaries that do use those functions. The actual implementation for those functions, the library, that is in package pam. That package is very unlikely to be missing (as it is essential), and has not been updated in years.

You can nevertheless check the status of that package: rpm -V pam

---

One does not need to use 'su' in most situations. The 'sudo' has similar function. (And so do 'ksu' and 'runuser', but for more specific cases.)

[sanketphadke]

Thank you @ jlehtone for your help.

Instead of using sudo su , I used sudo -i . it worked for me. I am able to switch to root user.

[lightman47]

there's also su -

[TrevorH]

I think it is su that is broken. I'd suggest trying `rpm -Va util-linux pam\*` and see if anything is reported as changed/missing.