In the case of research, universities are required to have an ethics board that reviews research proposals before actual research is conducted. Conducting research without an approval or misrepresenting the research project to the ethics board are pretty serious offenses.
Typically for research that involves people, participants in the research require having a consent form that is signed by participants, alongside a reminder for participants that they can withdraw that consent at any time without any penalties. It's pretty interesting that in this case, there seemed to have been no real consent required, and it would be interesting to know whether there has been an oversight by the ethics board or a misrepresentation of the research by the researchers.
It will be interesting to see whether the university applies a penalty to the professor (removal of tenure, termination, suspension, etc.) or not. The latter would imply that they're okay with unethical or misrepresented research being associated with their university, which would be pretty surprising.
In any case, it's a good thing that the Linux kernel maintainers decided that experimenting on them isn't acceptable and disrespectful of their contributions. Subjecting participants to experiments without their consent is a severe breach of ethical duty, and I hope that the university will apply the correct sanctions to the researchers and instigators.