rr

> Christian Brauner raised the problem of "flaky" tests, those that only pass sometimes. Ts'o said he has an internal version of his harness that allows tests to be marked flaky; if they fail, they are run three more times and are only reported if all of those fail. He has meant to add that feature into the public version, since it is useful, but has not found the time.

Why not run the fs tests in UML, as a normal process, under rr, so that any flakiness can be replayed and debugged deterministically? You could even use --chaos to explore more interleavings.