RFR: 8192897: NPE occurs on clhsdb jstack

[Sharath Ballal]

Fix looks good Yasumasa.


Thanks,
Sharath (Not a Reviewer)


-----Original Message-----
From: Yasumasa Suenaga [mailto:yasuenag at gmail.com] 
Sent: Saturday, December 02, 2017 4:19 AM
To: Sharath Ballal; serviceability-dev at openjdk.java.net
Subject: Re: RFR: 8192897: NPE occurs on clhsdb jstack

Hi Sharath,

I confirmed this issue with jshell and ClhsdbJstack with this change.
You need to run the VM in current jdk/hs.


Thanks,

Yasumasa


On 2017/12/02 1:22, Sharath Ballal wrote:
> Hi Yasumasa,
> I tried jhsdb with a simple HelloWorld (with -Xcomp) and did not see any exception.
> Your app does anything else ?
>
> Thanks,
> Sharath
>
>
> -----Original Message-----
> From: Yasumasa Suenaga [mailto:yasuenag at gmail.com]
> Sent: Friday, December 01, 2017 7:26 PM
> To: serviceability-dev at openjdk.java.net
> Subject: RFR: 8192897: NPE occurs on clhsdb jstack
>
> Hi all,
>
> I saw NPE when I run jstack on clhsdb as below:
>
> ----------------
> hsdb> jstack
> Deadlock Detection:
>
> No deadlocks found.
>
> "NonBlockingInputStreamThread" #27 daemon prio=5 tid=0x00007f0924674000 nid=0xf429 in Object.wait() [0x00007f08cf6fd000]
>     java.lang.Thread.State: WAITING (on object monitor)
>     JavaThread state: _thread_blocked
>   - java.lang.Object.wait(long) @bci=0 (Compiled frame; information may be imprecise)
>          - waiting on <no object reference available> Error occurred during stack walking:
> java.lang.NullPointerException
>          at jdk.hotspot.agent/sun.jvm.hotspot.runtime.CompiledVFrame.getMonitors(CompiledVFrame.java:131)
>          at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaVFrame.printLockInfo(JavaVFrame.java:125)
>          at jdk.hotspot.agent/sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:114)
>          at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor$26.doit(CommandProcessor.java:1073)
>          at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:1964)
>          at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.executeCommand(CommandProcessor.java:1934)
>          at jdk.hotspot.agent/sun.jvm.hotspot.CommandProcessor.run(CommandProcessor.java:1814)
>          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)
> ----------------
>
> It is caused by CompiledVFrame#getScope() returns null.
> We should consider it at CompiledVFrame#getMonitors().
>
> I uploaded a webrev. Could you review it?
> I checked this change with hotspot/jtreg/serviceability/sa on Linux x64.
>
>    http://cr.openjdk.java.net/~ysuenaga/JDK-8192897/webrev.00/
>
> We can reproduce this issue when we run the app with -Xcomp option.
> So I changed ClhsdbJstack.java to run with it.
>
>
> I cannot access mach5 and JPRT. So I need sponsor.
>
>
> Thanks,
>
> Yasumasa
>