As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE ENTERED THE COCKPIT AND CABIN AFTER TAKEOFF FROM ORD. ISOLATING THE PACKS DID NOT HELP. THE AIRCRAFT WAS RETURNED TO ORD WHERE IT LANDED WITHOUT INCIDENT. A BORESCOPE OF THE NR 2 ENGINE HPC SECOND STAGE FOUND THE AREA WET WITH OIL. THE VSV WAS ALSO FOUND TO BE WET WITH OIL. A NR 2 ENGINE CHANGE WILL BE PERFORMED.