New VM logging mechanism introduced in JDK9 allows dynamic change of the logging level, which means that level might change during a VM method execution. There should be a test checking that log level change will never cause a crash.

Test idea:
An application with several worker threads which allocate/release memory. In addition to those threads the application starts a couple of threads which set a random level of logging.

The test start this app with -Xlog:all for several seconds, expecting for no crash.