As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - COMING IN FOR LANDING AT ABOUT 2000 FEET SMELLED AN UNIDENTIFIED ODOR. AFTER LANDING FLIGHT ATTENDANTS INFORMED CREW OF A LITE HAZY SMOKE IN THE CABIN. SHUT OFF THE WING AND ENGINE ANTI-ICE AND THE SMOKE SUBSIDED. SUSPECT OIL LEAKING INTO APU INLET. REPLACED APU. SYSTEM GROUND CHECKED NORMAL OPERATION.