8274298: JFR Thread Sampler thread must not acquire malloc lock after suspending a thread because of possible deadlock

[mgronlun]

Greetings,

JDK-8233705 introduced a means to only iterate the incrementally tagged Klasses, instead of the entire set of Klasses in the JVM, as part of serializing metadata information. The newly tagged Klasses are enqueued onto a thread-local buffer using a load barrier. If the buffer runs out of space, a new buffer is accommodated, either from a free list or via a new allocation.

This is problematic for the JfrThreadSampler because the thread it has suspended could hold the malloc lock. For example, this could be the case if the suspended thread was in the process of deoptimization. The Deoptimization::UnrollBlock is a CHeapObj, and the vframes arrays use the NEW_C_HEAP_ARRAY macro.

The solution to this problem is to explicitly monitor the size of the thread-local buffer of the JfrThreadSampler thread, and pre-emptively renew it before thread suspension.

Testing: jdk_jfr, stress testing

Thanks
Markus

---

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Issue

• JDK-8274298: JFR Thread Sampler thread must not acquire malloc lock after suspending a thread because of possible deadlock

Reviewers

• Erik Gahlin (@egahlin - Reviewer) ⚠️ Review applies to 8b31f3a

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@mgronlun This change now passes all automated pre-integration checks.

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

8274298: JFR Thread Sampler thread must not acquire malloc lock after suspending a thread because of possible deadlock

Reviewed-by: egahlin

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At the time when this comment was updated there had been 64 new commits pushed to the master branch:

• 42d9b1b: 8277106: Cannot compile certain sources with --release
• ba86dd4: 8278445: ProblemList tools/jpackage/share/IconTest.java on macosx-x64
• 92aa75b: 8274903: Zero: Support AsyncGetCallTrace
• 8345453: 8272392: Lanai: SwingSet2. Black background on expanding tree node
• 9b74749: 8276660: Scalability bottleneck in java.security.Provider.getService()
• 2478158: 8277361: java/nio/channels/Channels/ReadXBytes.java fails with OOM error
• 8af3b27: 8277850: C2: optimize mask checks in counted loops
• 3e93e0b: 8276769: -Xshare:auto should tolerate problems in the CDS archive
• 79165b7: 8278324: Update the --generate-cds-archive jlink plugin usage message
• 40d726b: 8278310: Improve logging in CDS DynamicLoaderConstraintsTest.java
• ... and 54 more: https://git.openjdk.java.net/jdk/compare/d14f06a9630d2cd2a929d0e44ebe4bb10e20dbd4...master

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[mgronlun]

/integrate

[openjdk]

Going to push as commit 965ea8d.
Since your change was applied there have been 81 commits pushed to the master branch:

• 84baea7: 8278433: Use snippets in jdk.incubator.foreign documentation
• 1ea766d: 8278419: JFR jcmd option contract "This value cannot be changed once JFR has been initialized" is not enforced
• 62a7f5d: 8254318: Remove .hgtags
• d170682: 8278466: "spurious markup" warnings in snippets when building docs-reference
• 8ef1a23: 8278311: Debian packaging doesn't work
• 3524355: 8277882: New subnode ideal optimization: converting "c0 - (x + c1)" into "(c0 - c1) - x"
• 83e6a4c: 8255409: Support the new C_GetInterfaceList, C_GetInterface, and C_SessionCancel APIs in PKCS#11 v3.0
• 3cec700: 8278463: [test] Serialization WritePrimitive test revised for readFully test fails
• 03bf55f: 8277980: ObjectMethods::bootstrap throws NPE when lookup is null
• 3893f4f: 8278330: dump stack trace if the jvmti test nsk/jvmti/GetThreadState/thrstat002 is failed with wrong thread state
• ... and 71 more: https://git.openjdk.java.net/jdk/compare/d14f06a9630d2cd2a929d0e44ebe4bb10e20dbd4...master

Your commit was automatically rebased without conflicts.

[openjdk]

@mgronlun Pushed as commit 965ea8d.

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