On Wed, 28 Jul 2021 10:03:10 GMT, David Holmes <dhol...@openjdk.org> 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 pull request has now been integrated.
Changeset: 7e518f42
Author: David Holmes <dhol...@openjdk.org>
URL:
https://git.openjdk.java.net/jdk/commit/7e518f42c9346abdf0c8059b45d3dfef95ed69bb
Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
8269934: RunThese24H.java failed with EXCEPTION_ACCESS_VIOLATION in
java_lang_Thread::get_thread_status
Reviewed-by: stuefe, dcubed, sspitsyn
-------------
PR: https://git.openjdk.java.net/jdk/pull/4921
