As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT AT FL380, RECEIVED AN INTERCOM CALL FROM FLIGHT ATTENDANTS ADVISING OF AN ELECTRICAL ODOR IN THE RT CABIN BETWEEN ROWS 5 & 6. EMERGENCY DECLARED AND RETURNED TO DEPARTURE. FOUND OVERHEAD CEILING LIGHT AT 2ABC INOPERATIVE, THE LIGHT BALLAST FAILED CAUSING THE SMOKE. R & R CEILING LIGHT ASSEMBLY IAW MM.