RFR: 8316397: StackTrace/Suspended/GetStackTraceSuspendedStressTest.java failed with: SingleStep event is NOT expected [v4]

[Patricio Chilano Mateo]

On Fri, 28 Feb 2025 02:04:39 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> When trying to get the JvmtiThreadState_lock to create the JvmtiThreadState object:
>> 
>> 
>> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
>> V  [libjvm.so+0x14ba342]  Mutex::lock_contended(Thread*)+0x392  (interfaceSupport.inline.hpp:210)
>> V  [libjvm.so+0x14bbf7a]  Mutex::lock()+0x9a  (mutex.cpp:125)
>> V  [libjvm.so+0x120e9cb]  JvmtiEventControllerPrivate::thread_started(JavaThread*)+0x31b  (mutexLocker.hpp:196)
>> V  [libjvm.so+0x1212c08]  JvmtiExport::get_jvmti_thread_state(JavaThread*)+0x98  (jvmtiExport.cpp:424)
>> V  [libjvm.so+0x121e54a]  JvmtiExport::at_single_stepping_point(JavaThread*, Method*, unsigned char*)+0x7a  (jvmtiExport.cpp:1332)
>> V  [libjvm.so+0xed8728]  InterpreterRuntime::at_safepoint(JavaThread*)+0x118  (interpreterRuntime.cpp:1165)
>
> Uggghhh - I see. So why isn't this caught at ` ~ThreadBlockInVMPreprocess()`? Sorry I'm struggling to see the complete code.

We only allow suspension at `~ThreadBlockInVMPreprocess()` on very few cases where we know it's safe because there are no VM monitors held (the ones in ObjectMonitor, JvmtiRawMonitor and JavaThread::wait_for_object_deoptimization()). Otherwise the default is to not process suspend requests there.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23490#discussion_r1975494213