Seems like that would take care of roots for the bytecode's themselves, but not for "native" functions[1]. Allocating a new object could call gc[2], and native functions are using the native callstack. It seems like it would be easy to allocate in a native function and any unrooted references would be invalidated. In fact I see a case like that here[3]. That method creates a reference with `expect_concrete_object_at` and then calls gc with `new_java_lang_class_object`. It avoids UB by not using `arg` after the call that gc's, but there is nothing stopping you from using `arg` again (and having an invalid reference).

[1] https://github.com/andreabergia/rjvm/blob/main/vm/src/native...

[2] https://github.com/andreabergia/rjvm/blob/be9c54066c64a82879...

[3] https://github.com/andreabergia/rjvm/blob/be9c54066c64a82879...