This is a complicated question. First of all...What caused the crack? Does the ceiling framing need to be looked at? Was the roof load altered by more snow this year? Was a skylight or anything else added to the roof system?
A V-groove has to be opened where the crack was. It's not good enough to just tape over the problem. It'll happen again.
The crack is most likely at a joint.
If it is not the framing..I would cut the drywall back 2 studs from each side of the crack and then fill both joints.
There is a specific reason why it has cracked at this joint.