I know that Linus hates unit tests, but these kinds of scenarios are perfect for regression tests. The investigation of the issue took so long, that you'd really want to spend those extra few hours writing the test to save yourself investigation in the future. The patch doesn't include any comment about a race condition in the actual code, so let's assume that all the knowledge is more-or-less lost and forgotten in 12 months or so.

If Linus doesn't like unit tests, can't a separate entity keep their own independent unit test repository, test the kernel against it and report regressions? I think it would be a worthy project.