8267042: bug in monitor locking/unlocking on ARM32 C1 due to uninitialized BasicObjectLock::_displaced_header

[bulasevich]

Hi,

Could we have a review of this change?

The bug was discovered in ARM32 C1 monitor locking/unlocking: the
displaced header is not initialized to the non-zero value which results in deadlock.

Thanks,
Boris

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8267042: bug in monitor locking/unlocking on ARM32 C1 due to uninitialized BasicObjectLock::_displaced_header

Reviewers

• Dmitry Samersoff (@dsamersoff - Reviewer)

Contributors

• Chris Cole <chris@sageembedded.com>

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/4218/head:pull/4218
$ git checkout pull/4218

Update a local copy of the PR:
$ git checkout pull/4218
$ git pull https://git.openjdk.java.net/jdk pull/4218/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 4218

View PR using the GUI difftool:
$ git pr show -t 4218

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/4218.diff

[bridgekeeper]

👋 Welcome back bulasevich! 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]

@bulasevich The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 00: Full (6cf9a861)

[bulasevich]

/contributor add Chris Cole chris@sageembedded.com

[openjdk]

@bulasevich
Contributor Chris Cole <chris@sageembedded.com> successfully added.

[dsamersoff]

Looks good to me

[openjdk]

@bulasevich 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:

8267042: bug in monitor locking/unlocking on ARM32 C1 due to uninitialized BasicObjectLock::_displaced_header

Co-authored-by: Chris Cole <chris@sageembedded.com>
Reviewed-by: dsamersoff

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 355 new commits pushed to the master branch:

• f4d20b2: 8268900: com/sun/net/httpserver/Headers.java: Fix indentation and whitespace
• a051e73: Merge
• 9130b8a: 8268371: C2: assert(_gvn.type(obj)->higher_equal(tjp)) failed: cast_up is no longer needed
• 8545269: 8268676: assert(!ik->is_interface() && !ik->has_subklass()) failed: inconsistent klass hierarchy
• c98d508: 8268265: MutableSpaceUsedHelper::take_sample() hits assert(left >= right) failed: avoid overflow
• b66001a: 8268971: ProblemList tools/jpackage/windows/WinInstallerIconTest.java on win-x64
• 0011b52: 8264843: Javac crashes with NullPointerException when finding unencoded XML in

   tag

• 2047da7: 8265297: javax/net/ssl/SSLSession/TestEnabledProtocols.java failed with "RuntimeException: java.net.SocketException: Connection reset"
• 091bc4a: 8268353: Test libsvml.so is and is not present in jdk image
• 69d01b6: 8249899: jdk/javadoc/tool/InlineTagsWithBraces.java uses @ignore w/o bug-id
• ... and 345 more: https://git.openjdk.java.net/jdk/compare/37bc4e2e3c2968d7419dae4f421755b6f7d06090...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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[bulasevich]

/integrate

[openjdk]

Going to push as commit 8f2456e.
Since your change was applied there have been 356 commits pushed to the master branch:

• 5ae9a12: 8268964: Remove unused ReferenceProcessorAtomicMutator
• f4d20b2: 8268900: com/sun/net/httpserver/Headers.java: Fix indentation and whitespace
• a051e73: Merge
• 9130b8a: 8268371: C2: assert(_gvn.type(obj)->higher_equal(tjp)) failed: cast_up is no longer needed
• 8545269: 8268676: assert(!ik->is_interface() && !ik->has_subklass()) failed: inconsistent klass hierarchy
• c98d508: 8268265: MutableSpaceUsedHelper::take_sample() hits assert(left >= right) failed: avoid overflow
• b66001a: 8268971: ProblemList tools/jpackage/windows/WinInstallerIconTest.java on win-x64
• 0011b52: 8264843: Javac crashes with NullPointerException when finding unencoded XML in

   tag

• 2047da7: 8265297: javax/net/ssl/SSLSession/TestEnabledProtocols.java failed with "RuntimeException: java.net.SocketException: Connection reset"
• 091bc4a: 8268353: Test libsvml.so is and is not present in jdk image
• ... and 346 more: https://git.openjdk.java.net/jdk/compare/37bc4e2e3c2968d7419dae4f421755b6f7d06090...master

Your commit was automatically rebased without conflicts.

[openjdk]

@bulasevich Pushed as commit 8f2456e.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.