RFR: 8367725: Incorrect reading of oop in SuspendResumeManager::suspend while thread is blocked [v9]

[Leonid Mesnik]

On Wed, 17 Sep 2025 20:41:28 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   updated after David's feedback
>
> src/hotspot/share/runtime/suspendResumeManager.hpp line 63:
> 
>> 61: 
>> 62:   // The specific 'set_suspended' implementation for self suspend.
>> 63:   void set_suspended_with_id(int64_t id, bool register_vthread_SR);
> 
> Suggestion:
> 
>   // Sets the suspended state to `to`, applying to vthreads if `register_vthread_SR` is true.
>   void set_suspended(bool to, bool register_vthread_SR);
> 
>   // Sets the suspended state to true, applying to vthreads if `register_vthread_SR` is true.
>   // Applied to the thread with the given `id` and used when we can't extract the thread oop safely.
>   void set_suspended_with_id(int64_t id, bool register_vthread_SR);
> 
> These comments are far from perfect as it is actually hard to explain exactly what `thread` is being operated on - if any!

Really the comment 
```// Sets the suspended state to `to`, applying to vthreads if `register_vthread_SR` is true.```
looks incorrect to me. One might decide that the method doesn't set suspend state if for vthreads if `register_vthread_SR` is false. While the method always set suspend and might register or not vthreads to support SuspendAllVirtualThreads.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27317#discussion_r2356783702