I looked into it (https://old.reddit.com/r/linux/comments/mvd6zv/greg_khs_resp...). People from the University of Minnesota has 280 commits to the Linux kernel. Of those, 232 are from the three people directly implicated in this attack (that is, Aditya Pakki and the two authors of the paper), and the remaining 28 commits is from one individual who might not be directly involved.