On Wed, 27 Aug 2025 06:37:44 GMT, David Holmes <dhol...@openjdk.org> wrote:
>> (I realize this is a tangent, but maybe there is a separate bug here...) >> >>> To have a Class object it must have already undergone the "preparation" >>> part of linking (it is done at the end of loading when we create the class >>> mirror). >> >> If that's what "preparation" means, and Class.forName(name, false, loader) >> does not link the class, then posting the event here in >> InstanceKlass::link_class_impl() instead of earlier seems misplaced: >> >> https://github.com/openjdk/jdk/blob/c75534517729b903b63263cf64dc2ff841e3dcb1/src/hotspot/share/oops/instanceKlass.cpp#L1064 >> >> Class.forName(name, false, loader) would result in a prepared class but >> without the event being sent. > >> If that's what "preparation" means, and Class.forName(name, false, loader) >> does not link the class, then posting the event here in >> InstanceKlass::link_class_impl() instead of earlier seems misplaced > > @dean-long it seems the JVM TI "prepare" event is somewhat misnamed. It > states "At this point, class fields, methods, and implemented interfaces are > available, and no code from the class has been executed." but that neither > describes preparation, nor the rest of linking. You can only access fields > and methods after a class has been initialized! But lets take this elsewhere > if needed. @dholmes-ora, Thank you for review. > I'm not sure about the test, in particular the attempt to calculate > MIN_LINK_TIME_MS. It is very hard to see/know that you will actually induce > the desired race. Making a reliable regression test was a problem. `MIN_LINK_TIME_MS` is based on the reproducer from JDK-8277444 and my experiments on x86 and arm64 hosts. Maybe the time is not the best. As you wrote there is no way to know the race has happened. ------------- PR Comment: https://git.openjdk.org/jdk/pull/26863#issuecomment-3259506293
