It's a well known problem and they will repair the gun for you. The 442-1 was the first major revision and is when the frame was changed from the original to the "magnum" frame. They will take the guts out of your gun and install them into a new frame and barrel. If you have any modifications, such as a different rebound spring, take it out and put the original back in because they will discard those and put in the factory part.
My gun was an original frame version, so I got a whole new gun because they don't make that frame any longer.
As they say in the scooter commercials, "At no charge, absolutely no charge to me!". In my case I got the choice of a 442 or a 642 because mine was done in "Satin Nickel" finish, which they don't make any longer. Also, because mine was a no lock gun, they agreed to replace it with a no lock 642.
Call them, don't email them. Customer service is great on the phone, but so-so by email. They will send you a prepaid label to ship the gun back to them, you won't have to go through an FFL.
Interestingly enough, people who have shot them with cracked frames have not reported the barrels falling off. I don't know how many rounds I put through mine before I stumbled on a post over at the Smith-Wesson forum and looked at it. Cracks vary in width, but I doubt that they get smaller as time goes on.