[jdk11u-dev] RFR: 8322511: [11u] JfrCheckpointThreadClosure::do_thread crashes when fetching thread_id [v5]

[Jiawei Tang]

> Threads which are in the state of `is_attaching_via_jni` may have the NULL object as their `_threadObj` . 
> So the JVM will crash when calling `JfrCheckpointThreadClosure::do_thread()`.

Jiawei Tang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'openjdk:master' into master
 - Update full name
 - 8322511: JfrCheckpointThreadClosure::do_thread crashes when fetching thread_id

-------------

Changes:
  - all: https://git.openjdk.org/jdk11u-dev/pull/2413/files
  - new: https://git.openjdk.org/jdk11u-dev/pull/2413/files/0c58a66f..d9a69c9a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2413&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2413&range=03-04

  Stats: 117697 lines in 923 files changed: 32483 ins; 76040 del; 9174 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2413.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2413/head:pull/2413

PR: https://git.openjdk.org/jdk11u-dev/pull/2413