RFR: 8364314: java_lang_Thread::get_thread_status fails assert(base != nullptr) failed: Invalid base [v2]

[David Holmes]

On Wed, 30 Jul 2025 23:14:52 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> I just finished catching up on this other issue/PR:
>> 
>> [JDK-8361103](https://bugs.openjdk.org/browse/JDK-8361103) java_lang_Thread::async_get_stack_trace does not properly protect JavaThread
>> https://github.com/openjdk/jdk/pull/26119
>> 
>> And this comment from @sspitsyn stuck out to me w.r.t. to this fix:
>> 
>> https://github.com/openjdk/jdk/pull/26119#discussion_r2209135122
>> 
>> 
>> But, please, note that the JvmtiVTMSTransitionDisabler mechanism is enabled
>> only when there is a JVMTI agent. Otherwise, it has been disabled for scalability
>> purposes to exclude potentially high performance overhead at the VTMS
>> transition points.
>> 
>> 
>> The above comment from Serguei calls into question this suggested change that I posted on the PR:
>> 
>> https://github.com/openjdk/jdk/pull/26544/files#r2243188114
>> 
>> If the JvmtiVTMSTransitionDisabler only works when there's an agent attached,
>> I don't think we're protecting the carrier thread at all since it can become unmounted
>> at anytime when there's no agent.
>
>> If the JvmtiVTMSTransitionDisabler only works when there's an agent attached, I don't think we're protecting the carrier thread at all since it can become unmounted at anytime when there's no agent.
> 
> Right. The issue was discovered several weeks ago: https://bugs.openjdk.org/browse/JDK-8361913 Work in progress

Thanks for the re-review @alexmenkov !

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PR Comment: https://git.openjdk.org/jdk/pull/26544#issuecomment-3152495124