RFR: JDK-8310584: GetThreadState reports blocked and runnable for pinned suspended virtual threads

[Serguei Spitsyn]

On Thu, 13 Jul 2023 19:18:38 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

> The change fixes handling of "suspended" bit in VT state.
> The code looks very strange.
> java_lang_VirtualThread::RUNNING == 3, so line 803 clears JVMTI_THREAD_STATE_ALIVE(1) and JVMTI_THREAD_STATE_TERMINATED(2)
> Per log this code came from loom repo with VT integration.
> 
> Testing: tier1-4, updated GetThreadStateMountedTest.java

@alexmenkov Do you consider backporting this to 21?

src/hotspot/share/prims/jvmtiEnvBase.cpp line 804:

> 802:   if (ext_suspended && ((state & JVMTI_THREAD_STATE_ALIVE) != 0)) {
> 803:     state |= JVMTI_THREAD_STATE_SUSPENDED;
> 804:   }

One question unrelated to this bug and your fix.
I wonder if any check and handling is needed for the case:
  `if (ext_suspended && ((state & JVMTI_THREAD_STATE_ALIVE) == 0))`
Not sure this condition is even possible. But do we need to add an assert here?

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PR Comment: https://git.openjdk.org/jdk/pull/14878#issuecomment-1635229248
PR Review Comment: https://git.openjdk.org/jdk/pull/14878#discussion_r1263261620