who -r displays no output

UNIX AIX
1

Hello. I have an AIX machine at 6100-00.

We had some strange activity since filling up /tmp. One symptom is that who -r displays no output. It doesn't hang just no output is displayed.

We are going to boot the machine, but prior to that I'd like to dig a bit to see what may be causing the symptom. Where does who -r get its information?

Thanks!