RFR: 8253429: Error reporting should report correct state of terminated/aborted threads

[Zhengyu Gu]

On Fri, 25 Sep 2020 14:23:44 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> For some non-JavaThread, their object instances can outlast threads' lifespan. For example, we still can query/report
>> thread's state after thread terminated.
>> But the query/report currently returns wrong state. E.g. a terminated thread appears to be alive and seemly has valid
>> thread stack, etc.
>> This patch sets non-JavaThread's state to ZOMBIE just before it terminates, so that we can distinguish terminated
>> thread from live thread.
>> Also, thread should not report its SMR info, if it has terminated or it never started (thread->osthread() == NULL).
>> 
>> Note: Java thread does not have such issue, its thread object is deleted before thread terminates.
>
> src/hotspot/share/runtime/thread.cpp line 955:
> 
>> 953:     }
>> 954:   } else {
>> 955:     st->print(" Aborted");
> 
> Not sure this is reachable and if it is then I'm not sure what state the thread is actually in. If a Thread never gets
> an osThread() it isn't started so shouldn't be locatable by any means.

so, you prefer "ShouldNotReachHere()" ?

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PR: https://git.openjdk.java.net/jdk/pull/341