RFR: 8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state [v4]

[Serguei Spitsyn]

On Thu, 14 Aug 2025 00:01:29 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Leonid Mesnik has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - added _
>>  - wong phase
>
> src/hotspot/share/prims/jvmtiExport.cpp line 1838:
> 
>> 1836:   {
>> 1837:     ThreadInVMfromJava tiv(thread);
>> 1838:     state = get_jvmti_thread_state(thread);
> 
> The issue I see is that `get_jvmti_thread_state()` can safepoint for virtual threads (and now also for platform threads because of `~ThreadInVMfromJava`), which brings us back to the bug 8255452 was trying to fix: if there is a return oop at the top of the stack, it could become invalid if a GC occurs. I think we will have to unconditionally save the return value in case it's an oop, before doing anything else.

Thank you, Patricio! Good catch and suggestion.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26713#discussion_r2276043185