RFR: 8314225: SIGSEGV in JavaThread::is_lock_owned [v3]

[Kevin Walls]

On Wed, 1 May 2024 10:00:13 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> src/hotspot/share/runtime/vframeArray.cpp line 317:
>> 
>>> 315:     BasicObjectLock* src = _monitors->at(index);
>>> 316:     top->set_obj(src->obj());
>>> 317:     assert(ObjectSynchronizer::current_thread_holds_lock(thread, Handle(thread, src->obj())), "should be held, before move_to");
>> 
>> Same comment as above, may need to check for null obj.
>
> Not sure how `obj` can be null in this code. ???

That is fetching from an index in the MonitorChunk* _monitors, so if we recognise null in element->fill_in() when populating MonitorChunk*, seems good to recognise it here in vframeArrayElement::unpack_on_stack()?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18940#discussion_r1586858264