RFR: 8367725: Incorrect reading of oop in SuspendResumeManager::suspend while thread is blocked [v4]

[Francesco Andreuzzi]

On Tue, 16 Sep 2025 18:20:13 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> The
>> `SuspendResumeManager::suspend(bool register_vthread_SR)`
>> has an issue while suspend current virtual thread. The suspend tries to access vthread oop field to read vthread id after thread is blocked. 
>> 
>> Seems, that this case is not used by our debugger and was not covered by tests. I found it using jtreg test thread virtual factory plugin. I updated existing test to reproduce this problem. The easiest way is to suspend current virtual thread using plain SuspendThread. 
>> 
>> The fix added some "asymmetry"  in suspend/resume mechanism which is required because self-suspend doesn't have resume counterpart.
>
> Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   typo fixed

src/hotspot/share/runtime/suspendResumeManager.cpp line 92:

> 90:   if (register_vthread_SR) {
> 91:     assert(_target->is_vthread_mounted(), "sanity check");
> 92:       JvmtiVTSuspender::register_vthread_suspend(id);

Suggestion:

    JvmtiVTSuspender::register_vthread_suspend(id);

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PR Review Comment: https://git.openjdk.org/jdk/pull/27317#discussion_r2353373334