RFR: 8288139: JavaThread touches oop after GC barrier is detached [v4]

[Daniel D. Daugherty]

On Fri, 17 Jun 2022 00:52:15 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> I want to fix this bug in JDK19 since it is a blocker for @zhengyu123. I want to
>> keep this fix small and focused on the exact crash associated with the bug.
>> 
>> Yes, threadObj() or deeper is a better place. No argument, but I plan to do that
>> as a new hunt and I expect there to be many problems and I don't want to hold
>> up this fix for additional hunting. If I find more issues, then we'll determine how
>> to get them fixed in JDK19.
>
> Okay

New bug:
[JDK-8289091](https://bugs.openjdk.org/browse/JDK-8289091) move oop safety check from SharedRuntime::get_java_tid() to JavaThread::threadObj()

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PR: https://git.openjdk.org/jdk19/pull/21