8372591: assert(!current->cont_fastpath() || freeze.check_valid_fast_path()) failed

[rm-gh-8]

Backporting JDK-8372591: assert(!current->cont_fastpath() || freeze.check_valid_fast_path()) failed.

This PR fixes a critical bug in OSR (On-Stack Replacement) handling with continuations where _cont_fastpath is incorrectly set when an OSR frame has an interpreted caller. The issue occurs because OSR frames are created from the sender's unextended_sp (not sp), but _cont_fastpath was being set to the sender's sp, potentially pointing outside valid stack space.

This mismatch can cause _cont_fastpath to be prematurely cleared while interpreted frames remain on the stack, leading to incorrect execution of the freeze fast path (which should only run when all frames are compiled) and resulting in crashes.

The fix changes OSR_migration_begin to use the sender's unextended_sp for _cont_fastpath, ensuring proper stack boundary tracking.

This backport has internal demand.

Ran related tests on linux-x64, linux-aarch64, macos-aarch64 and windows-x64:

make test TEST=test/jdk/jdk/internal/vm

Results attached:

linux-aarch64-specific-test.log
linux-x64-specific-test.log
macos-aarch64-specific-test.log
windows-x64-specific-test.log

---

Progress

• Change must not contain extraneous whitespace
• JDK-8372591 needs maintainer approval
• Commit message must refer to an issue

Issue

• JDK-8372591: assert(!current->cont_fastpath() || freeze.check_valid_fast_path()) failed (Bug - P3 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/144/head:pull/144
$ git checkout pull/144

Update a local copy of the PR:
$ git checkout pull/144
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/144/head

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Checkout this PR locally:
$ git pr checkout 144

View PR using the GUI difftool:
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https://git.openjdk.org/jdk25u-dev/pull/144.diff

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[bridgekeeper]

👋 Welcome back rm-gh-8! 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]

@rm-gh-8 This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8372591: assert(!current->cont_fastpath() || freeze.check_valid_fast_path()) failed

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 9 new commits pushed to the master branch:

• 5c423ee: 8371559: Intermittent timeouts in test javax/net/ssl/Stapling/HttpsUrlConnClient.java
• 1e72690: 8342175: MemoryEaterMT fails intermittently with ExceptionInInitializerError
• bdf4939: 8373984: Check for macos 11 in CGraphicsDevice.m can be removed
• ... and 6 more: https://git.openjdk.org/jdk25u-dev/compare/fae7da1f91bfd947eac4f98e8b888909f692deae...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

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➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[openjdk]

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

[openjdk]

⚠️ @rm-gh-8 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 (81ccef5b)

[rm-gh-8]

/approval request for backport of JDK-8372591: assert(!current->cont_fastpath() || freeze.check_valid_fast_path()) failed.

This PR changes OSR_migration_begin to use the sender's unextended_sp for _cont_fastpath, ensuring proper stack boundary tracking.

This backport has internal demand.

High-medium risk - Incorrect stack pointer management could lead to memory corruption or crashes and changes to OSR handling might affect compilation performance or stack management overhead.

[openjdk]

@rm-gh-8
8372591: The approval request has been created successfully.

[GoeLin]

Hi Roland,

if the backport only has internal demand, just bring it to your internal VM.
Please give a reason why this is important for OpenJDK.

[rm-gh-8]

Hi Goetz,

Our customers utilize the JDK in a highly varied amount of use cases and issues that occur indicate that it may likely manifest for OpenJDK users, and would be a worthwhile consideration.