RFR: 8288532: additional review changes for JDK-8286830 [v3]

[Daniel D. Daugherty]

On Tue, 21 Jun 2022 15:46:09 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   VMThread can get to check in AsyncExceptionHandshake() dtr via a bailout.
>
>> I forgot that install_async_exception() can delete the AsyncExceptionHandshake which calls the AsyncExceptionHandshake dtr:
>> 
>> ```
>> 
>> Current thread (0x0000ffff001bab70):  VMThread "VM Thread" [stack: 0x0000fffee8110000,0x0000fffee8310000] [id=661857] _threads_hazard_ptr=0x0000fffc8021f770, _nested_threads_hazard_ptr_cnt=0
>> 
>> Stack: [0x0000fffee8110000,0x0000fffee8310000],  sp=0x0000fffee830e030,  free space=2040k
>> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
>> V  [libjvm.so+0x1909960]  AsyncExceptionHandshake::~AsyncExceptionHandshake()+0x230
>> V  [libjvm.so+0x1908a7c]  JavaThread::install_async_exception(AsyncExceptionHandshake*)+0x4c
>> V  [libjvm.so+0x190ace8]  InstallAsyncExceptionHandshake::do_thread(Thread*)+0x38
>> V  [libjvm.so+0xe67d20]  HandshakeOperation::do_handshake(JavaThread*)+0x13c
>> V  [libjvm.so+0xe68cec]  HandshakeState::try_process(HandshakeOperation*)+0x23c
>> V  [libjvm.so+0xe6b384]  VM_HandshakeAllThreads::doit()+0x1f4
>> V  [libjvm.so+0x19f2788]  VM_Operation::evaluate()+0x168
>> V  [libjvm.so+0x1a1c9d4]  VMThread::evaluate_operation(VM_Operation*)+0x154
>> V  [libjvm.so+0x1a1e1bc]  VMThread::inner_execute(VM_Operation*)+0x45c
>> V  [libjvm.so+0x1a1e374]  VMThread::loop()+0xc4
>> V  [libjvm.so+0x1a1e4a0]  VMThread::run()+0xcc
>> V  [libjvm.so+0x1907bb8]  Thread::call_run()+0xf8
>> V  [libjvm.so+0x16033a4]  thread_native_entry(Thread*)+0x104
>> C  [libpthread.so.0+0x78f8]  start_thread+0x188
>> ```
> Ah right, the VMThread could take over that synchronous handshake! Thanks for the investigation Dan. The last update looks good.

@pchilano - Thanks for the re-review.
@dholmes-ora - Thanks for the review.

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PR: https://git.openjdk.org/jdk19/pull/32