RFR: 8308978: regression with a deadlock involving FollowReferences

Tue May 30 23:06:03 UTC 2023

The change fixes regression from JDK-8299414.
There is a deadlock between JvmtiVTMSTransitionDisabler and EscapeBarrier when virtual threads are in mount/unmount transition:
EscapeBarrier requests deoptimization which requires thread suspension.
JvmtiVTMSTransitionDisabler ctor waits until all in progress VTMS transitions complete, but they cannot be completed as thread is suspended.
To avoid the deadlock mount/unmount transitions should be completed before EscapeBarrier stuff.

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Commit messages:
 - fix

Changes: https://git.openjdk.org/jdk/pull/14233/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14233&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308978
  Stats: 10 lines in 1 file changed: 6 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14233.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14233/head:pull/14233

PR: https://git.openjdk.org/jdk/pull/14233