I've flown ORD-ICN on KE and OZ and ORD-NRT-ICN on UA many times. They've all given the DPRK a wide berth. For the flights to ICN, they've done as stated above -- flown to Japan, then turned back north to ICN. I seem to recall someone saying that they once when the other way around through Russia and China, but that seems long.

Call me selfish, but one of the things that will make me happy when reunification comes is that it'll shave a good 45-60 minutes off the flying time to ICN.