/dev/mem,kmem,port is restricted

Question

Why do I receive the errors in my log?

Apr  4 16:38:42 185 kernel: Lockdown: cpkeyclt: /dev/mem,kmem,port is restricted; see man kernel_lockdown.7
Apr  4 16:38:45 185 kernel: Lockdown: envtype: /dev/mem,kmem,port is restricted; see man kernel_lockdown.7

Answer

These messages are from Secure Boot which is based on the Unified Extensible Firmware Interface (UEFI), the low-level system management software that runs before handing over control to the operating system. Secure Boot allows only approved operating systems to run on the machine.

Disabling Secure Boot for your server through the BIOS will stop these messages.

Additional Resources

"Lockdown: X: Y is restricted, see man kernel_lockdown.7" messages in the kernel log