RFR: 8369482: JVMTI + Loom: JDK-8368159 introduced safepoint poll in disallowed state [v3]

[Patricio Chilano Mateo]

On Mon, 13 Oct 2025 08:32:03 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> [JDK-8368159](https://bugs.openjdk.org/browse/JDK-8368159) added `JvmtiExport::has_frame_pops(JavaThread* thread)`
>> which calls `JvmtiExport::get_jvmti_thread_state();` which may safepoint.
>> 
>> Example stack trace:
>> 
>> V [libjvm.dylib+0x125f888] VMError::report(outputStream*, bool)+0x1b68 (javaThread.cpp:375)
>> V [libjvm.dylib+0x1263184] VMError::report_and_die(int, char const*, char const*, char*, Thread*, unsigned char*, void const*, void const*, char const*, int, unsigned long)+0x55c
>> V [libjvm.dylib+0x5de268] print_error_for_unit_test(char const*, char const*, char*)+0x0
>> V [libjvm.dylib+0x9427ec] JavaThread::check_for_valid_safepoint_state()+0x120
>> V [libjvm.dylib+0xe7e4e4] Mutex::lock(Thread*)+0x48
>> V [libjvm.dylib+0xbbb198] JvmtiThreadState::state_for(JavaThread*, Handle)+0x200
>> V [libjvm.dylib+0xc462ec] JvmtiEventControllerPrivate::thread_started(JavaThread*)+0x1a0
>> V [libjvm.dylib+0xc493a4] JvmtiExport::get_jvmti_thread_state(JavaThread*, bool)+0xc0
>> V [libjvm.dylib+0xc5078c] JvmtiExport::has_frame_pops(JavaThread*)+0x24
>> V [libjvm.dylib+0x59c398] freeze_epilog(JavaThread*, ContinuationWrapper&, freeze_result)+0xf8
>> V [libjvm.dylib+0x59b6e8] Config<(oop_kind)0, CardTableBarrierSet>::freeze(JavaThread*, long*)+0x6f4
>> V [libjvm.dylib+0x59a4d4] int freeze<Config<(oop_kind)0, CardTableBarrierSet>>(JavaThread*, long*)+0x108
>> 
>> 
>> I suggest we do double checked on `JvmtiExport::can_post_frame_pop()` and move the `ContinuationWrapper::SafepointOp` scope.
>
> Axel Boldt-Christmas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Check !cont.entry()->is_virtual_thread()

Looks good to me, thanks.

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Marked as reviewed by pchilanomate (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27716#pullrequestreview-3331727767