8277444: Data race between JvmtiClassFileReconstituter::copy_bytecodes and class linking

[chadrako]

Backport of https://bugs.openjdk.org/browse/JDK-8277444. Trivial conflict (NULL vs nullptr)

This fixes a race condition that occurs when a class is simultaneously retransformed via the Instrumentation API and linked. This can lead to invalid bytecode which will cause a VerifyError. Even worse, if class verifying is turned off, which it is by default for java.* classes, this will cause the JVM to crash/segfault.

The included test test/jdk/java/lang/instrument/RetransformBigClassTest.java fails before the patch and passes after

---

Progress

• JDK-8277444 needs maintainer approval
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8277444: Data race between JvmtiClassFileReconstituter::copy_bytecodes and class linking (Bug - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk17u-dev.git pull/3955/head:pull/3955
$ git checkout pull/3955

Update a local copy of the PR:
$ git checkout pull/3955
$ git pull https://git.openjdk.org/jdk17u-dev.git pull/3955/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 3955

View PR using the GUI difftool:
$ git pr show -t 3955

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk17u-dev/pull/3955.diff

Using Webrev

Link to Webrev Comment

[chadrako]

Waiting to request maintainer approval until backport is merged in newer JDKs

[bridgekeeper]

👋 Welcome back chadrako! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @chadrako This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (83b174fd)