RFR: 8337331: crash: pinned virtual thread will lead to jvm crash when running with the javaagent option [v3]

[Jiawei Tang]

On Mon, 29 Jul 2024 22:34:46 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> Jiawei Tang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   changes according to reviewers' advice
>
> src/hotspot/share/prims/jvmtiExport.cpp line 970:
> 
>> 968:     if (_thread->is_in_any_VTMS_transition()) {
>> 969:       return; // no events should be posted if thread is in any VTMS transition
>> 970:     }
> 
> This is not right place to fix it.
> 
> This would be better:
> 
> @@ -1091,8 +1091,8 @@ bool JvmtiExport::post_class_file_load_hook(Symbol* h_name,
>    if (JvmtiEnv::get_phase() < JVMTI_PHASE_PRIMORDIAL) {
>      return false;
>    }
> -  if (JavaThread::current()->is_in_tmp_VTMS_transition()) {
> -    return false; // skip CFLH events in tmp VTMS transition
> +  if (thread->is_in_any_VTMS_transition()) {
> +    return; // no events should be posted if thread is in any VTMS transition
>    }
>  
>    JvmtiClassFileLoadHookPoster poster(h_name, class_loader,
> 
> 
> Also, there is a check in the constructor `JvmtiClassFileLoadHookPoster()`:
> 
>     if (_thread->is_in_any_VTMS_transition()) {
>       return; // no events should be posted if thread is in any VTMS transition
>     }
> 
> It is better to replace it with assert. With the right check in the `JvmtiExport::post_class_file_load_hook()` we should never call this constructor and `poster.post()` when in a VTMS transition.

Change it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20373#discussion_r1696407776