The unit test CodePatchSyncRequestVisitor fails from time to time. See http://jikesrvm.anu.edu.au/job/x86-pre-commit-main-repo/45/console for a recent report.
It seems that the test method codePatchingWorksWhenAThreadIsWaiting is not always terminating (even with a much more generous timeout than the test currently uses).
Edit: After deactivating the method, a similar problem occurs with the test for patching while sleeping. I've deactivated the tests for sleeping and parking in ae11b1fbb6b05b6b77bdf087896420fc9d9d62af. The test for suspend was deactivated in 0a6f1e4c121d43a7c53ec986d758b0643bb29839.
IA32, not yet tested on PPC