On Sat, 26 Oct 2024 06:34:08 GMT, Serguei Spitsyn <sspit...@openjdk.org> wrote:
>> src/hotspot/share/prims/jvmtiEnvBase.cpp line 667:
>>
>>> 665:
>>> 666: javaVFrame*
>>> 667: JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition,
>>> javaVFrame* jvf) {
>>
>> reworked function looks much better! Now it's clear what the function does
>> and I have a question what it should do.
>> The function checks `@JvmtiMountTransition` annotation first even if the
>> thread is in transition.
>> If `@JvmtiMountTransition` is present, the code doesn't care about
>> `@ChangesCurrentThread` (and doesn't case about `@JvmtiMountTransition` if
>> in_transition + `@ChangesCurrentThread`).
>> But we have 2 methods in VirtualThread class (`switchToCarrierThread()` and
>> `switchToVirtualThread()`) with both annotations.
>> So if the function is called when `switchToCarrierThread` is on top, the
>> function skips this frame, but if the thread calls some other function
>> without `@JvmtiMountTransition` annotation from `switchToCarrierThread`, the
>> function returns `switchToCarrierThread`.
>
> Good catch, thanks.
> These two functions are impacted by temporary VTMS transitions. It seems we
> fail to hide frames in these transitions while we skip the JVMTI events in
> their context. I'll try to fix this issue.
I'd suggest to file a separate bug on this issue as it has to be tested well.
Please, let me know if you are okay with it.
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PR Review Comment: https://git.openjdk.org/jdk/pull/21397#discussion_r1817700598
