On Wed, 31 Mar 2021 05:27:05 GMT, David Holmes <[email protected]> wrote:
>> src/hotspot/share/runtime/handshake.cpp line 485:
>>
>>> 483: } else {
>>> 484: // Asynchronous may block so they may not execute
>>> ~PreserveExceptionMark before safepointing
>>> 485: // in outer loop.
>>
>> Sorry, I don't understand the comment.
>
> I think this relates to why the PEM was moved from the loop-scope to the sync
> op case only. That said it isn't clear why we need the HM or PEM.
I guess it should be "... must not execute ~PreserveExceptionMark ..."
~PreserveExceptionMark calls _thread->pending_exception() which is an oop and
that would be illegal as the vm could be at a safepoint when the async
handshake returns.
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PR: https://git.openjdk.java.net/jdk/pull/3191
