Jdmpview from Java 22 does not work for system core files from Java 17.

[manqingl]

It looks to me some generated classes were deleted from openj9.dtfj.jmod. This breaks the backward compatibility of Jdmpview

/common/public/tools/ddr/x/jdk-20.1+8/bin/java -Xshareclasses:none -version
openjdk version "22.0.1-beta" 2024-04-16
IBM Semeru Runtime Open Edition 22.0.1+8-202406280047 (build 22.0.1-beta+8-202406280047)
Eclipse OpenJ9 VM 22.0.1+8-202406280047 (build master-22eaa4d435, JRE 22 Linux amd64-64-Bit Compressed References 20240628_193 (JIT enabled, AOT enabled)
OpenJ9 - 22eaa4d
OMR - 47a9d248d
JCL - e29be76fa based on jdk-22.0.1+8)

/common/public/tools/ddr/x/jdk-22.0.1+8/bin/jdmpview -J-Xshareclasses:none -core core.20240726.063619.30790.0001.dmp
DTFJView version 4.29.5, using DTFJ version 1.12.29003
Loading image from DTFJ...

Warning: native libraries are not available for core.20240726.063619.30790.0001.dmp
For a list of commands, type "help"; for how to use "help", type "help help"
Available contexts (* = currently selected context) :

Source : file:///ecurep/sf/TS016/603/TS016603209/2024-07-26/core.20240726.063619.30790.0001.dmp.zip_unpack/scratch/core/core.20240726.063619.30790.0001.dmp
*0 : PID: 56618 : JRE 17 Linux amd64-64 (build 17.0.9+9) IBM Semeru Runtime Open Edition

!stackslots 0x0096b300
Error executing DDR command !stackslots 0x0096b300 : null
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:118)
at java.base/java.lang.reflect.Method.invoke(Method.java:586)
at openj9.dtfjview/com.ibm.jvm.dtfjview.CombinedContext.executeDDRInteractiveCommand(CombinedContext.java:258)
at openj9.dtfjview/com.ibm.jvm.dtfjview.CombinedContext.execute(CombinedContext.java:169)
at openj9.dtfjview/com.ibm.jvm.dtfjview.Session.execute(Session.java:813)
at openj9.dtfjview/com.ibm.jvm.dtfjview.Session.execute(Session.java:767)
at openj9.dtfjview/com.ibm.jvm.dtfjview.tools.ToolsRegistry.executeJdmpviewCommand(ToolsRegistry.java:183)
at openj9.dtfjview/com.ibm.jvm.dtfjview.tools.ToolsRegistry.execute(ToolsRegistry.java:107)
at openj9.dtfjview/com.ibm.jvm.dtfjview.tools.ToolsRegistry.execute(ToolsRegistry.java:88)
at openj9.dtfjview/com.ibm.jvm.dtfjview.tools.ToolsRegistry.recordAndExecute(ToolsRegistry.java:72)
at openj9.dtfjview/com.ibm.jvm.dtfjview.Session.runInteractive(Session.java:741)
at openj9.dtfjview/com.ibm.jvm.dtfjview.Session.run(Session.java:665)
at openj9.dtfjview/com.ibm.jvm.dtfjview.DTFJView.launch(DTFJView.java:52)
at openj9.dtfjview/com.ibm.jvm.dtfjview.DTFJView.main(DTFJView.java:46)
Caused by: java.lang.NoClassDefFoundError: com.ibm.j9ddr.vm29.pointer.generated.J9JITGPRSpillAreaPointer
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker$1.allAlgorithms(StackWalker.java:131)
at com.ibm.j9ddr.vm29.j9.AlgorithmPicker.pickAlgorithm(AlgorithmPicker.java:43)
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker.getImpl(StackWalker.java:138)
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker.walkStackFrames(StackWalker.java:99)
at com.ibm.j9ddr.vm29.tools.ddrinteractive.commands.StackWalkCommand.run(StackWalkCommand.java:144)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.Context.tryCommand(Context.java:229)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.Context.execute(Context.java:202)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.DDRInteractive.execute(DDRInteractive.java:356)
at openj9.dtfj/com.ibm.j9ddr.command.CommandReader.processLine(CommandReader.java:78)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.DDRInteractive.processLine(DDRInteractive.java:331)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
... 13 more
Caused by: java.lang.ClassNotFoundException: J9JITGPRSpillAreaPointer is not in core file
at openj9.dtfj/com.ibm.j9ddr.StructureReader.getPointerClassBytes(StructureReader.java:1127)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.getPointerClass(J9DDRClassLoader.java:227)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.findClass(J9DDRClassLoader.java:129)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.loadClass(J9DDRClassLoader.java:206)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:1102)
... 24 more

[manqingl]

@pshipton @keithc-ca FYI

[keithc-ca]

I can confirm that J9JITGPRSpillArea is not in j9ddr.dat in 17.0.9+9.
However, I don't see any references to that class either. Were you using any DDR plugins?

[manqingl]

I used the jdmpview tool in the !stackslots command (!stackslots 0x0096b300). The text in the top of this page has the details. @keithc-ca

[keithc-ca]

So no DDR plugins?

[manqingl]

No DDR plugins (assuming !stackslots is counted as a DDR command, but not as a DDR plugin).

[gacholio]

J9JITGPRSpillArea was added here: af13691

I believe I added the structure (Jack committed it along with more changes). Did I miss something? There's no direct reference to the structure in the DDR code.

[keithc-ca]

There is an inlined instance in J9VMContinuation which is referenced in DDR code, but as far as I can tell, only in support of !continuationstack and !continuationstackslots which have guards that the core is from jdk19 or newer (which should not apply to the situation discussed here).

[manqingl]

Looks like the exception happens when a new instance of StackWalker_29_V0() is created at StackWalker.java:131 :

java.lang.ClassNotFoundException: J9JITGPRSpillAreaPointer is not in core file
at openj9.dtfj/com.ibm.j9ddr.StructureReader.getPointerClassBytes(StructureReader.java:1133)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.getPointerClass(J9DDRClassLoader.java:229)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.findClass(J9DDRClassLoader.java:129)
at openj9.dtfj/com.ibm.j9ddr.J9DDRClassLoader.loadClass(J9DDRClassLoader.java:206)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:1075)
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker$1.allAlgorithms(StackWalker.java:131)
at com.ibm.j9ddr.vm29.j9.AlgorithmPicker.pickAlgorithm(AlgorithmPicker.java:43)
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker.getImpl(StackWalker.java:138)
at com.ibm.j9ddr.vm29.j9.stackwalker.StackWalker.walkStackFrames(StackWalker.java:99)
at com.ibm.j9ddr.vm29.tools.ddrinteractive.commands.StackWalkCommand.run(StackWalkCommand.java:144)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.Context.tryCommand(Context.java:229)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.Context.execute(Context.java:202)
at openj9.dtfj/com.ibm.j9ddr.tools.ddrinteractive.DDRInteractive.execute(DDRInteractive.java:356)

[keithc-ca]

I think this is a consequence of #18014. I'm hoping that this can be remedied by declaring a fictitious (and unused) field of J9JITGPRSpillArea which will allow that structure to be referenced. If I put a test build together, could you test it on a troublesome system dump, @manqingl? If so, which platform works for you?

[manqingl]

I can test in a Linux or AIX platform. @keithc-ca