RFR: 8373366: HandshakeState should disallow suspend ops for disabler threads [v11]

[Serguei Spitsyn]

On Thu, 15 Jan 2026 06:01:39 GMT, David Holmes <dholmes at openjdk.org> wrote:

> I can't say that I understand what is happening in [JDK-8375362](https://bugs.openjdk.org/browse/JDK-8375362) but I do wonder if we need to get all the current VT issues resolved (in Loom repo?) before trying to update mainline. Maybe they are distinct issues but maybe there is some overlap

We've never had sufficient test coverage for `InterruptThread` in combination with `SuspendThread`. New test introduced in this PR found this new problem which I understand. It is better/simpler to address separately. It might require more investigation and testing even though I have a potential fix in mind.

> test/hotspot/jtreg/serviceability/jvmti/vthread/ThreadStateTest2/ThreadStateTest2.java line 48:
> 
>> 46:  *  - VT-2: a virtual thread: in a loop calls JVMTI InterruptThread(VT-0) and GetThreadState(VT-1)
>> 47:  *  - main: a platform thread: in a loop invokes native method testSuspendResume which suspends and resumes VT-2
>> 48:  * The JVMTI functionis above install a MountUnmountDisabler for target virtual thread (VT-0 or VT-1).
> 
> Suggestion:
> 
>  * The JVMTI functions above install a MountUnmountDisabler for target virtual thread (VT-0 or VT-1).

Good catch, thanks! Fixed now.

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PR Comment: https://git.openjdk.org/jdk/pull/28740#issuecomment-3753828862
PR Review Comment: https://git.openjdk.org/jdk/pull/28740#discussion_r2693702756