On Tue, 12 Jul 2022 20:00:22 GMT, Roger Riggs <rri...@openjdk.org> wrote:
> The test `java/lang/ClassLoader/loadLibraryUnload/LoadLibraryUnloadTest.java` > Fails intermittently when expected output from a subprocess is not found. > > I suspect a race between the Cleaner that is going to call JNI_OnUnload (in > NativeLibraries.java:377) when the ClassLoader is no longer referenced and > the test code that exits as soon as it detects that the p.Class1 is no longer > referenced. > > The proposed fix is to create a canary object referenced by the native > library and released when the library is unloaded. > The Java side of the test provides the canary object and uses a WeakReference > to wait for it to be released. > When released the child process exits and the driver test will find all of > the output it expects. Yes, waiting for only the final Class1 loaded from the class loaders is suspect. There is no deterministic order to the clearing/queuing of the WeakReferences/PhantomReferences to the classes or the respective class loaders. The test is looking for the call to the library's "_OnUnload" function to be printed to the output. That happens sometime after the (successful) class loader is reclaimed; waiting on that reclamation isn't sufficient. I'll remove the waiting on the Class1. ------------- PR: https://git.openjdk.org/jdk/pull/9474
