If GM could buy it back for a premium in the future - I hate to think what that premium would be.
Finally, I seriously doubt that any funds from GM operations outside the U.S. will end up going to pay back obligations to the U.S. tax payers anytime soon.
The bailout was done by the U.S. government to benefit a broad swath of U.S. citizens - employees, surviving dealers, and the automotive supply chain.
There should be no practical expectation that funds are going to flow in to the U.S. from non US operations anymore than funds going the other way. Such expectations simply are not realistic inspite of what some people may feel is "right".