After upgrading from pam-0.77-27 to pam-0.77-29 I can no longer su from root to some other user without entering a password. This breaks, e.g., the innd startup. I imagine this must have something to do with selinux, but I'm not, as far as I know, running with selinux enabled -- I've certainly never taken any steps to enable it.
Yup it is missing the is_selinux_enabled check. Fixed in pam-0.77-30 Thanks.