Virtual thread memory leak because TrackingRootContainer keeps threads

[Michal Domagala]

According to https://openjdk.org/jeps/444,

"Unlike platform thread stacks, virtual thread stacks are not GC roots."

But jdk.internal.vm.ThreadContainers.RootContainer.TrackingRootContainer#VTHREADS
keeps (hard) references to each virtual thread. Effectively,
virtual threads are GC roots.

I described full example here:
https://stackoverflow.com/questions/78596905/why-virtual-thread-is-not-garbage-collected-when-not-reachable

The problem was not visible since
https://bugs.openjdk.org/browse/JDK-8309406, because before the change,
VTHREADS "keep" was not enabled and i guess nobody cares memory leak.

But after the change every JVM is affected.

A workaround for memory leak is set jdk.trackAllThreads=false

Best regards
Michal Domagala
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