I upgraded from 8.4.2 to 8.4.3, and I couldn't start postgres. This was
printed on STDERR
FATAL: data directory "path-to-my-data-dir" has group or world access
DETAIL: Permissions should be u=rwx (0700).
This change was not documented in the release notes, and I don't think
permission != 700 should be a fatal error. I purposely set o+x to let
any user be able to read the log files.