RFR: 8274196: Crashes in VM_HeapDumper::work after JDK-8252842

[Lin Zang]

On Fri, 24 Sep 2021 15:01:26 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> I agree the flag here and at the place of lock acquiring  seems problematic. I will try to see whether I can use `Mutex::_safepoint_check_never` here and get rid of the assert.
>
> yes
>     void Mutex::check_no_safepoint_state(Thread* thread) {
>        check_block_state(thread);
>        assert(!thread->is_active_Java_thread() || _safepoint_check_required != _safepoint_check_always,
>               "This lock should always have a safepoint check for Java threads: %s",
>               name());
>      }
> 
> yes, we exclude the check for a non-java thread, which I thought was an odd exclusion last time I looked.  I pass the tests in sun/tools/jmap/BasicJMapTest.java so maybe leave it for now?

I agree, maybe a new issue could be created for tracking this.

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PR: https://git.openjdk.java.net/jdk/pull/5681