RFR: 8340698: JVMTI FRAME_POP event is sometimes missed if NotifyFramePop is called as a method is returning [v4]

[Serguei Spitsyn]

On Wed, 16 Oct 2024 21:50:19 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   review: resolved comments from Alex and Chris
>
> test/hotspot/jtreg/serviceability/jvmti/events/NotifyFramePopStressTest/libNotifyFramePopStressTest.cpp line 84:
> 
>> 82:       deallocate(jvmti, jni, name);
>> 83:       deallocate(jvmti, jni, (void*)last_notify_method);
>> 84:       fatal(jni, "FramePop event in wrong method\n");
> 
> This is the main purpose for this test. It used to just set `failed` and then continue to run to detect additional errors, and then java side of the test calls `failed()` to detect the failure. Now you exit the test process when there is a failure. There is actually no purpose served for the `failed` flag anymore.

> Have you verified that the test still detects the bug? In other words, if you disabled the fix, does the test fail? I was just a bit worried that with all the changes to it, it might not be still be properly detecting the bug, and I looked in the mach5 history and don't see this test failing for a couple of weeks now.

The test is failing locally with event in a wrong method as expected.
But the latest changes broke the test. Now it is failing at `deallocate(jvmti, jni, csig)`.
I suspect it is related to the latest changes for `last_notify_method` but have not proved it yet.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21468#discussion_r1803970580