RFR: 8225354: serviceability/jvmti/ModuleAwareAgents/ThreadStart failed with Didn't get ThreadStart events in VM early start phase! [v2]

[Alex Menkov]

On Tue, 24 Jun 2025 06:54:19 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> The test incorrectly expects that some system threads must be started in the `early JVMTI_PHASE_START` phase. However, there is a race here and it is possible that the `JVMTI_PHASE_LIVE` phase is reached before any system thread has been started. The fix is to wait for the first `THREAD_START` event at the `VM_INIT` event.
>> 
>> The update includes some other changes and minor refactoring:
>>  - the file `libMAAThreadStart.c` has been renamed to `libMAAThreadStart.cpp`
>>  - the test library `jvmti_common.hpp` is used where it is possible
>>  - static variable `printdump` has been removed
>>  - the static block with `loadLibrary` has been removed from the `MAAThreadStart.java`
>>  
>>  Testing:
>>   - ran the modified test locally
>>   - TBD: submit mach5 tiers 1-5
>
> Serguei Spitsyn has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - corrected the Copyright line
>  - small corrections and indentation fixes

I don't see how waiting in VMInit can help here.
Phase is set before posting VMInit events.

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PR Comment: https://git.openjdk.org/jdk/pull/25948#issuecomment-3001822541