Comment 5 for bug 651537

There's a whole pile of dependency loops here, just to name a few:
pam <-> coreutils <-> libselinux <-> findutils <-> coreutils

This makes ordering quite a lottery, for example in this case hitting the pam %post failure depends on the exact order in which the packages are fed into the transaction: apparently that order in yum happened to change between 5.2 and 5.3. And the ordering depends on the exact set of dependencies present in the transaction, another change here is that rpm itself used to have %pre require shadow-utils which in turn depends on libselinux which is involved in the loops above... which might've masked the underlying loops in this case.

The dependency loops are what really needs fixing, but it's possible to work around with adding dependency whiteout to rpm config, this seems to cure at least this particular case:

%_dependency_whiteout \
coreutils>pam