As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - AFTER TAKEOFF FLIGHT ATTENDANT REPORTED SMOKE FILLING BACK OF CABIN FROM LIGHTS IN OVERHEAD AND SIDEWALLS. FOUND APU OIL LEAK. APU WAS REPLACED PER CARD 49 96 82. ACCOMPLISHED BURN OUT OF PNEUMATIC DUCTING. SYSTEM GROUND CHECKED NORMAL OPERATION.