Comment # 29 on bug 1094762 from Franck Bui

Michal perhaps you can spot something in the meantime.

To sum up, right after the upgrade of systemd package, the dbus daemon is no
more able to use 'org.freedesktop.systemd1' service:

> May 27 11:39:24 linux-phe7 dbus-daemon[693]: [system] Failed to activate service 'org.freedesktop.systemd1': timed out (service_start_timeout=25000ms)

PID1 doesn't seem to have crashed.

It might be worth noting that polkit and dbus are reloading their configuration
while systemd is reexecuted (due to the package upgrade).