Re: SA Debug attach to another jvm version possible?

Egor Ushakov Tue, 21 Aug 2018 03:19:51 -0700

Thank you all! It is much better now.

Related question: documentation for java 10https://docs.oracle.com/javase/10/docs/specs/jpda/conninv.html#sa-pid-attaching-connectorstill states that the debug server should be launched with sa-jdi.jar inclasspath, though there's no such jar in the jdk any more.

java \
    -classpath ${JAVA_HOME}/lib/sa-jdi.jar \
    sun.jvm.hotspot.jdi.SADebugServer
How should it be launched on jdk 9, 10?


Thanks,
Egor

On 21-Aug-18 11:55, Sharath Ballal wrote:

Hi David,

I opened https://bugs.openjdk.java.net/browse/JDK-8209781 for it.

Thanks,
Sharath


-----Original Message-----
From: David Holmes
Sent: Tuesday, August 21, 2018 7:47 AM
To: Sharath Ballal; Egor Ushakov; serviceability-dev@openjdk.java.net 
serviceability-dev@openjdk.java.net
Subject: Re: SA Debug attach to another jvm version possible?

Hi Sharath,

On 21/08/2018 3:07 AM, Sharath Ballal wrote:

Hello Egor,

By default, SA checks for the exact match of the version between the
debugger and the debuggee.  If you

In that case we need to fix the referenced documentation that states otherwise.

Cheers,
David

want SA to ignore the version, you need to provide the 
"-Dsun.jvm.hotspot.runtime.VM.disableVersionCheck" option to the java launcher from the 
command line.  This is the case even if you are not using the debug server.  However since 'jstack' 
and similar tools don’t take the "-D" option of java, you can invoke it as follows:

java   -cp <jdk>/lib/sa-jdi.jar   
-Dsun.jvm.hotspot.runtime.VM.disableVersionCheck   sun.jvm.hotspot.tools.JStack   
localhost

If you invoke the SA tools with this option, you will get a warning that the 
version check has been disabled.

Example:
$ <jdk>/bin/java -cp <jdk>/lib/sa-jdi.jar
-Dsun.jvm.hotspot.runtime.VM.disableVersionCheck sun.jvm.hotspot.tools.JStack 
localhost Attaching to remote server localhost, please wait...
WARNING: You have disabled SA and VM version check. You may be using 
incompatible version of SA and you may see unexpected results.
Debugger attached successfully.
Server compiler detected.
JVM version is 25.121-b13
Deadlock Detection:

No deadlocks found.

Thread t@ 2804: (state = BLOCKED)


Thread t@ 2803: (state = BLOCKED)
   - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
   - java.lang.ref.ReferenceQueue.remove(long) @bci=59, line=143 (Interpreted 
frame)
   - java.lang.ref.ReferenceQueue.remove() @bci=2, line=164 (Interpreted frame)
   - java.lang.ref.Finalizer$FinalizerThread.run() @bci=36, line=209
(Interpreted frame)


Thread t@ 2802: (state = BLOCKED)
   - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
   - java.lang.Object.wait() @bci=2, line=502 (Interpreted frame)
   - java.lang.ref.Reference.tryHandlePending(boolean) @bci=54, line=191 
(Interpreted frame)
   - java.lang.ref.Reference$ReferenceHandler.run() @bci=1, line=153
(Interpreted frame)


Thread t@ 2798: (state = BLOCKED)
   - java.lang.Thread.sleep(long) @bci=0 (Interpreted frame)
   - HelloWorld.main(java.lang.String[]) @bci=72, line=15 (Interpreted
frame)


Hope this helps.

Thanks,
Sharath


-----Original Message-----
From: Egor Ushakov [mailto:egor.usha...@jetbrains.com]
Sent: Monday, August 20, 2018 3:42 PM
To: serviceability-dev@openjdk.java.net
serviceability-dev@openjdk.java.net
Subject: SA Debug attach to another jvm version possible?

Hi all,

documentation for SA Debug Server Attaching Connector here:
https://docs.oracle.com/javase/8/docs/technotes/guides/jpda/conninv.ht
ml#Connectors states that the SADebugServer has to run on the same vm
version as the debugee process, but "the debugger does not have to be the same bit 
size and version."
However any attempts to connect from another version fail with 
sun.jvm.hotspot.runtime.VMVersionMismatchException.

Please help, what do I do wrong (locally for simplicity):
- start the debugee process with jdk1.8.0_162  - get the PID
- start "jdk1.8.0_162\bin>jsadebugd.exe PID" - all starts well
- trying to attach jstack, jdb or whatever from another version:
jdk1.8.0_152\bin>jstack localhost
Attaching to remote server localhost, please wait...
Error attaching to remote server:
sun.jvm.hotspot.runtime.VMVersionMismatchException: Supported versions
are 25.152-b16. Target VM is 25.162-b12
sun.jvm.hotspot.debugger.DebuggerException:
sun.jvm.hotspot.runtime.VMVersionMismatchException: Supported versions
are 25.152-b16. Target VM is 25.162-b12

jdk1.8.0_152\bin>jdb -connect
"sun.jvm.hotspot.jdi.SADebugServerAttachingConnector:debugServerName=localhost"
java.io.IOException
           at
sun.jvm.hotspot.jdi.SADebugServerAttachingConnector.attach(SADebugServerAttachingConnector.java:106)
           at
com.sun.tools.example.debug.tty.VMConnection.attachTarget(VMConnection.java:519)
           at
com.sun.tools.example.debug.tty.VMConnection.open(VMConnection.java:328)
           at com.sun.tools.example.debug.tty.Env.init(Env.java:63)
           at com.sun.tools.example.debug.tty.TTY.main(TTY.java:1082)
Caused by: java.lang.reflect.InvocationTargetException
           at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
           at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
           at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
           at java.lang.reflect.Method.invoke(Method.java:498)
           at
sun.jvm.hotspot.jdi.SADebugServerAttachingConnector.createVirtualMachine(SADebugServerAttachingConnector.java:72)
           at
sun.jvm.hotspot.jdi.SADebugServerAttachingConnector.attach(SADebugServerAttachingConnector.java:91)
           ... 4 more
Caused by: sun.jvm.hotspot.debugger.DebuggerException:
sun.jvm.hotspot.runtime.VMVersionMismatchException: Supported versions are 
25.152-b16. Target VM is 25.162-b12
           at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:435)
           at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:305)
           at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:183)
           at
sun.jvm.hotspot.jdi.VirtualMachineImpl.createVirtualMachineForServer(VirtualMachineImpl.java:241)
           ... 10 more
Caused by: sun.jvm.hotspot.runtime.VMVersionMismatchException: Supported 
versions are 25.152-b16. Target VM is 25.162-b12
           at sun.jvm.hotspot.runtime.VM.checkVMVersion(VM.java:227)
           at sun.jvm.hotspot.runtime.VM.<init>(VM.java:294)
           at sun.jvm.hotspot.runtime.VM.initialize(VM.java:370)
           at sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:431)
           ... 13 more

Thanks!

--
Egor Ushakov
Software Developer
JetBrains
http://www.jetbrains.com
The Drive to Develop


--
Egor Ushakov
Software Developer
JetBrains
http://www.jetbrains.com
The Drive to Develop

Re: SA Debug attach to another jvm version possible?

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