JDK-8280601 : ClhsdbThreadContext.java test is triggering codecache related asserts
  • Type: Bug
  • Component: hotspot
  • Sub-Component: svc-agent
  • Affected Version: 19
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2022-01-25
  • Updated: 2022-10-27
  • Resolved: 2022-02-01
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JDK 19
19 b08Fixed
Related Reports
Relates :  
JDK-8250801 - Add clhsdb "threadcontext" command
Description
When running serviceability/sa/ClhsdbThreadContext.java , the following failure was seen:

 sun.jvm.hotspot.utilities.AssertionFailure: Should have found CodeBlob
at jdk.hotspot.agent/sun.jvm.hotspot.utilities.Assert.that(Assert.java:32)
at jdk.hotspot.agent/sun.jvm.hotspot.utilities.PointerFinder.find(PointerFinder.java:140)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaThread.printThreadContextOn(JavaThread.java:493)
at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor$46.doit(CommandProcessor.java:1699)
at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2212)
at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2182)
at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.run(CommandProcessor.java:2053)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:112)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500)
]
 exitValue = -1

java.lang.RuntimeException: Test ERROR java.lang.RuntimeException: 'Thread "Common-Cleaner"' missing from stdout/stderr

at ClhsdbThreadContext.main(ClhsdbThreadContext.java:101)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:577)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:833)

The root cause is:

r9: 0x00000176ee380000Error: sun.jvm.hotspot.utilities.AssertionFailure: Should have found CodeBlob
sun.jvm.hotspot.utilities.AssertionFailure: Should have found CodeBlob

This caused the clhsdb threadcontext command to abort, so it never got around to dumping the context of the Common-Cleaner thread.

It looks like in PionterFinder.find() SA has hit some edge case with the address, and found that it is in the codecache, but there is no CodeBlob representing that address, so it asserts. I think instead it should just adapt and later PointerLocation should print something like "Not in CodeBlob".

So far this has only happened on Windows-x64 in a run with the following JVM args:

-Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation -XX:+VerifyOops

Most likely -Xcomp is what triggered it. It seems to have happened consistently in 3 separate runs with this option, so it likely 100% reproducible.
Comments
The fix was integrated in jdk-19+8-437.
03-02-2022
Changeset: 85d839fb Author: Chris Plummer <cjplummer@openjdk.org> Date: 2022-02-01 23:02:06 +0000 URL: https://git.openjdk.java.net/jdk/commit/85d839fb4f3f820d130ea95f9a54ae137a95c20a
01-02-2022
I ran into a couple of other asserts listed below. It looks like since dumping the threadcontext can result in using PointerFinder with fairly random addresses, it is doing a much better job of stress testing PointerFinder than is done by other tests. The root issue in all these asserts is that a random address in the codecache can either be outside of any CodeBlob, or can map to a CodeBlob that is not yet initialized or could even have been freed. The two newest asserts seem to be a result of the latter: sun.jvm.hotspot.utilities.AssertionFailure: found wrong CodeBlob at jdk.hotspot.agent/sun.jvm.hotspot.utilities.Assert.that(Assert.java:32) at jdk.hotspot.agent/sun.jvm.hotspot.code.CodeCache.findBlobUnsafe(CodeCache.java:140) at jdk.hotspot.agent/sun.jvm.hotspot.utilities.PointerFinder.find(PointerFinder.java:138) at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaThread.printThreadContextOn(JavaThread.java:493) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor$46.doit(CommandProcessor.java:1702) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2215) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2185) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.run(CommandProcessor.java:2056) at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:112) at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44) at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281) at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500) sun.jvm.hotspot.utilities.AssertionFailure: Should have found CodeBlob at jdk.hotspot.agent/sun.jvm.hotspot.utilities.Assert.that(Assert.java:32) at jdk.hotspot.agent/sun.jvm.hotspot.utilities.PointerFinder.find(PointerFinder.java:140) at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaThread.printThreadContextOn(JavaThread.java:493) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor$46.doit(CommandProcessor.java:1702) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2215) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:2185) at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.run(CommandProcessor.java:2056) at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:112) at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44) at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281) at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500) PointerFinder and PointerLocation need to be prepared to handled these asserts, and any other exception thrown.
27-01-2022
A pull request was submitted for review. URL: https://git.openjdk.java.net/jdk/pull/7217 Date: 2022-01-25 22:07:37 +0000
26-01-2022