Delay in sys_keyctl() syscall when executing sudo, su or login via ssh in RHEL6

Issue

Sometimes on some systems running RHEL6 there is a variable delay when userspace executes "sudo" or "su" or user tries to login via ssh. Delay can be from few milliseconds and up to 10 seconds and not constant but changes during different attempts.
In this issue userspace tool like strace can be used to narrow down the problem to sys_keyctl() syscall that handled by kernel. Thus delay is caused by kernel while handling this syscall.