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

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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 - Requested)

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[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)

[bridgekeeper]

@chadrako This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[chadrako]

/keepalive

[openjdk]

@chadrako The pull request is being re-evaluated and the inactivity timeout has been reset.

[bridgekeeper]

@chadrako This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[chadrako]

/keepalive

[openjdk]

@chadrako The pull request is being re-evaluated and the inactivity timeout has been reset.

[bridgekeeper]

@chadrako This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[bridgekeeper]

@chadrako This pull request has been inactive for more than 8 weeks and will now be automatically closed. If you would like to continue working on this pull request in the future, feel free to reopen it! This can be done using the /open pull request command.

[chadrako]

/open

[openjdk]

@chadrako This pull request is now open

[chadrako]

/approval request A clean backport that 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. This patch has been in jdk25 and Corretto 17 for 6 months.

[openjdk]

@chadrako
8277444: The approval request has been created successfully.