On Wed, 28 Jul 2021 14:22:07 GMT, Thomas Stuefe <[email protected]> wrote:
>> If a thread is attaching via JNI and has not yet created its Thread object
>> it can be caught in a ThreadSnapshot during a thread dump (VM_DumpThreads)
>> of all threads**, and the threadObj() will be NULL, so we can't pass it to
>> get_thread_status().
>>
>> ** JMM dumpThreads API
>>
>> The initial fix simply checks for a NULL threadObj() and reports thread
>> status NEW in that case.
>>
>> Alternatively we could filter the attaching thread out completely in
>> VM_DumpThreads::doit by expanding:
>>
>> if (jt->is_exiting() ||
>> jt->is_hidden_from_external_view()) {
>> // skip terminating threads and hidden threads
>> continue;
>> }
>>
>> to also check jt->is_attaching_via_jni().
>>
>> Note that higher-level code already filters out ThreadSnapshots with NULL
>> threadObj() anyway so we could go either way.
>>
>> Testing: manual hacks - see bug report.
>> - tier 1-3 sanity testing
>>
>> Thanks,
>> David
>
> This looks good to me.
>
> ..Thomas
Thanks for the reviews @tstuefe and @dcubed-ojdk !
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PR: https://git.openjdk.java.net/jdk/pull/4921
