How to repair a hairline crackin ceiling from walking in attic

You could try to fill them with paint but if they are to big for that you may have to fill them with drywall compound and letting it dry and then sponge the excess off and then paint

Crack was caused by ceiling beam deflection. Install knee wall to shorten span.

Chuck

If you ever go back in the attic it will crack again. If you just want a quick patch kknife some spackle or drywall compoundon the crack. A better fix is to clean out the crack and use drywall tape and mud. The best fix is to strengthen the rafters or main beam.