Yes, there is a good chance there is already a 10 digit hash collision in the Linux repository. But if you pick an arbitrary commit to cite in a research paper

Yes, there is a good chance there is already a 10 digit hash collision in the Linux repository. But if you pick an arbitrary commit to cite in a research paper, it's still 1 in a million that that particular commit has a collision. And this is for a repo which has to be in the 99.999th percentile of number of commits.