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List:       openjdk-serviceability-dev
Subject:    RE: Issue with 8192897: NPE occurs on clhsdb jstack
From:       stewartd.qdt <stewartd.qdt () qualcommdatacenter ! com>
Date:       2018-02-08 13:13:46
Message-ID: 47d1f562fe5e4079863b5413693b6ef6 () NASANEXM01E ! na ! qualcomm ! com
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Yes, this is consistently reproducible on my system. I'm happy to provide more \
information if it will help. If I knew more about how the Java stack worked, I could \
do more of this debugging myself. Is it ever legal to have a Method pointer of null?

Daniel

-----Original Message-----
From: Jini George [mailto:jini.george@oracle.com] 
Sent: Wednesday, February 7, 2018 11:34 PM
To: stewartd.qdt <stewartd.qdt@qualcommdatacenter.com>; serviceability-dev \
<serviceability-dev@openjdk.java.net>; David Holmes <david.holmes@oracle.com>; \
                Sharath Ballal <sharath.ballal@oracle.com>; yasuenag@gmail.com
Subject: Re: Issue with 8192897: NPE occurs on clhsdb jstack

Thanks for this, Daniel. Is this consistently reproducible on the
Aarch64 system with the -Xcomp part of the test ?

Thanks,
Jini

On 2/7/2018 10:12 PM, stewartd.qdt wrote:
> I am getting Null Pointer Exceptions with both ClhsdbJstack.java and 
> ClhsdbFindPC.java. It appears the addition of testing with  '-Xcomp` 
> causing a Method to come back as null during the stack walk. I have 
> included the results of the Jstack test (the FindPC is similar) for 
> the Xcomp section below. I have created bug JDK-8196969 
> <https://bugs.openjdk.java.net/browse/JDK-8196969>.  The full .jtr is 
> attached there.  I am not familiar enough with the Java stack to know 
> if having  a null Method pointer is valid or not.
> 
> Thanks,
> 
> Daniel
> 
> hsdb>
> 
> Command line: 
> ['/home/stewartd/openjdk/OpenJDK/hs/build/linux-aarch64-normal-server-release/images/jdk/bin/java' \
>  '-Xcomp' '-cp' 
> '/home/stewartd/openjdk/OpenJDK/hs/JTwork/classes/serviceability/sa/ClhsdbJstack.d:/home/stewartd/openjdk/OpenJDK/hs/JTwork/classes/test/lib' \
>  'jdk.test.lib.apps.LingeredApp' 
> '717a6b55-bcf8-405e-9d5a-afe1212f0fc6.lck' ]
> 
> Started LingeredApp (-Xcomp) with pid 23731
> 
> Starting clhsdb against 23731
> 
> Warning! JS Engine can't start, some commands will not be available.
> 
> hsdb> Deadlock Detection:
> 
> No deadlocks found.
> 
> "Common-Cleaner" #22 daemon prio=8 tid=0x0000ffffa0528000 nid=0x5d2d 
> in
> Object.wait() [0x0000fffe427de000]
> 
> java.lang.Thread.State: TIMED_WAITING (on object monitor)
> 
> JavaThread state: _thread_blocked
> 
> - java.lang.ref.ReferenceQueue.remove(long) @bci=59, line=151, 
> pc=0x0000ffff892af7c4, Method*=0x0000fffe49851a98 (Compiled frame; 
> information may be imprecise)
> 
> - waiting to lock <0x0000000101c956f0> (a
> java.lang.ref.ReferenceQueue$Lock)
> 
> - jdk.internal.ref.CleanerImpl.run() @bci=65, line=148, 
> pc=0x0000ffff892ac8e4, Method*=0x0000fffe49ab23d8 (Compiled frame)
> 
> - java.lang.Thread.run() @bci=11, line=844, pc=0x0000ffff892a9d30,
> Method*=0x0000fffe49738ee0 (Compiled frame)
> 
> - jdk.internal.misc.InnocuousThread.run() @bci=20, line=134, 
> pc=0x0000ffff892a9d30, Method*=0x0000fffe49aba318 (Compiled frame)
> 
> Locked ownable synchronizers:
> 
> - None
> 
> "Signal Dispatcher" #4 daemon prio=9 tid=0x0000ffffa04a6800 nid=0x5d05 
> runnable [0x0000000000000000]
> 
> java.lang.Thread.State: RUNNABLE
> 
> JavaThread state: _thread_blocked
> 
> Locked ownable synchronizers:
> 
> - None
> 
> "Finalizer" #3 daemon prio=8 tid=0x0000ffffa0494000 nid=0x5d04 in
> Object.wait() [0x0000fffe492ee000]
> 
> java.lang.Thread.State: WAITING (on object monitor)
> 
> JavaThread state: _thread_blocked
> 
> - java.lang.ref.ReferenceQueue.remove(long) @bci=59, line=151, 
> pc=0x0000ffff888e15a0, Method*=0x0000fffe49851a98 (Interpreted frame)
> 
> - waiting to lock <0x0000000101c09528> (a
> java.lang.ref.ReferenceQueue$Lock)
> 
> - java.lang.ref.ReferenceQueue.remove() @bci=2, line=172, 
> pc=0x0000ffff888e12c0, Method*=0x0000fffe49851b40 (Interpreted frame)
> 
> - java.lang.ref.Finalizer$FinalizerThread.run() @bci=37, line=216, 
> pc=0x0000ffff888e12c0, Method*=0x0000fffe49856cb0 (Interpreted frame)
> 
> Locked ownable synchronizers:
> 
> - None
> 
> "Reference Handler" #2 daemon prio=10 tid=0x0000ffffa0492000 
> nid=0x5d03 waiting on condition [0x0000fffe494ee000]
> 
> java.lang.Thread.State: RUNNABLE
> 
> JavaThread state: _thread_blocked
> 
> - java.lang.ref.Reference.processPendingReferences() @bci=0, line=166, 
> pc=0x0000ffff888e15a0, Method*=0x0000fffe49733100 (Interpreted frame)
> 
> - java.lang.ref.Reference.access$000() @bci=0, line=44, 
> pc=0x0000ffff888e15a0, Method*=0x0000fffe49733788 (Interpreted frame)
> 
> - java.lang.ref.Reference$ReferenceHandler.run() @bci=0, line=138, 
> pc=0x0000ffff888e15a0, Method*=0x0000fffe4984ffa0 (Interpreted frame)
> 
> Locked ownable synchronizers:
> 
> - None
> 
> "main" #1 prio=5 tid=0x0000ffffa0010000 nid=0x5cb5 waiting on 
> condition [0x0000ffffa5d2e000]
> 
> java.lang.Thread.State: TIMED_WAITING (sleeping)
> 
> JavaThread state: _thread_blocked
> 
> Error occurred during stack walking:
> 
> Locked ownable synchronizers:
> 
> - None
> 
> hsdb>
> 
> ----------System.err:(147/8216)----------
> 
> Attaching to process 23463, please wait...
> 
> javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not 
> a function in sa.js at line number 54
> 
> javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not 
> a function in sa.js at line number 54
> 
> Attaching to process 23731, please wait...
> 
> javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not 
> a function in sa.js at line number 54
> 
> javax.script.ScriptException: TypeError: sapkg.runtime.VM.getVM is not 
> a function in sa.js at line number 54
> 
> java.lang.NullPointerException
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java
> > 83)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor$26.doit(CommandProc
> essor.java:1073)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(Comm
> andProcessor.java:1966)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(Comm
> andProcessor.java:1936)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.run(CommandProcesso
> r.java:1816)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:99)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:40)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java
> > 191)
> 
> at
> jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:439)
> 


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