_dbus_loop_iterate become busy loop when the connection disconnected or never have an active connection.
What version of dbus are you using?
How can this busy loop be reproduced? Is it in dbus-daemon or in something else?
More information requested 3 years ago and not supplied; there isn't enough here to diagnose or fix a bug, so closing as WORKSFORME.
If you have this symptom, please open a new bug (or reopen, if you are the original reporter) with more information.