RFR: JDK-8164913: JVMTI.agent_load dcmd should show useful error message

[serguei.spitsyn at oracle.com]

Hi Yasumasa,


On 9/6/16 15:28, Yasumasa Suenaga wrote:
> Hi Serguei,
>
>>>> I think you would have to justify why this should be a P3 rather 
>>>> than P4 issue.
>>
>>
>> This needs to be answered as well.
>
> I've sent it in previous email as below:
>
>>>>> This problem is that jcmd shows incorrect status when JVMTI agent 
>>>>> cannot
>>>>> be attached.
>>>>> I think this problem should be fixed in 9 GA.
>>>>> The users who want.to attach JVMTI agent want to know
>>>>> whether it succeed.


Then you have to add this justification to the bug report and set the 
priority to P3.
Not sure, what else is required by the RDP1 process.

Thanks,
Serguei


>
>
> Yasumasa
>
>
> On 2016/09/07 3:48, serguei.spitsyn at oracle.com wrote:
>> Hi Yasumasa,
>>
>> Please, find my comment below.
>>
>>
>> On 9/6/16 06:06, Yasumasa Suenaga wrote:
>>> Hi David,
>>>
>>>> Is this something specific to code added in 9? If so that is 
>>>> motivation as we should not have a new feature with known bugs if 
>>>> we can avoid it. But if this already exists in JDK 8 and is a long 
>>>> standing "bug" ...
>>>
>>> The change for jvmtiExport.cpp can apply jdk8u:
>>>
>>> http://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot/file/d55ea2916525/src/share/vm/prims/jvmtiExport.cpp#l2270 
>>>
>>>
>>> I think HotSpot in jdk8u ignores exception and return JNI_OK even if 
>>> Agent_OnAttach() fails.
>>> OTOH, the change for diagnosticCommand.cpp affects jdk9 only.
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> On 2016/09/06 9:54, David Holmes wrote:
>>>> Hi Yasumasa,
>>>>
>>>> On 1/09/2016 1:47 PM, Yasumasa Suenaga wrote:
>>>>> Hi all,
>>>>>
>>>>> I think RDP1 has been started.
>>>>> Cannot I fix this?
>>>>
>>>> "P4-P5 bugs should, in general, be left to future releases unless they
>>>> only affect documentation, demos, or tests, in which case they 
>>>> should be
>>>> identified as such with the "noreg-doc", "noreg-demo", and 
>>>> "noreg-self"
>>>> labels, respectively." [1]
>>>>
>>>> This is due to the need to stabilize changes as we head towards GA.
>>>>
>>>> I think you would have to justify why this should be a P3 rather 
>>>> than P4 issue.
>>
>>
>> This needs to be answered as well.
>>
>>
>> Thanks,
>> Serguei
>>
>>
>>>> Is this something specific to code added in 9? If so that is 
>>>> motivation as we should not have a new feature with known bugs if 
>>>> we can avoid it. But if this already exists in JDK 8 and is a long 
>>>> standing "bug" ...
>>>>
>>>> David
>>>>
>>>> [1] 
>>>> http://mail.openjdk.java.net/pipermail/jdk9-dev/2016-August/004777.html 
>>>>
>>>>
>>>>
>>>>> This problem is that jcmd shows incorrect status when JVMTI agent 
>>>>> cannot
>>>>> be attached.
>>>>> I think this problem should be fixed in 9 GA.
>>>>> The users who want.to attach JVMTI agent want to know
>>>>> whether it succeed.
>>>>>
>>>>> Yasumasa
>>>>>
>>>>>
>>>>> 2016/08/29 15:42 "Yasumasa Suenaga" <yasuenag at gmail.com
>>>>> <mailto:yasuenag at gmail.com>>:
>>>>>
>>>>>         This comment no longer matches the code and should be 
>>>>> deleted:
>>>>>
>>>>>         2412       // Agent_OnAttach executed so completion status 
>>>>> is JNI_OK
>>>>>         2413       st->print_cr("return code: %d", result);
>>>>>
>>>>>
>>>>>     Thanks David!
>>>>>     I removed it in new webrev.
>>>>>
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8164913/webrev.01/
>>>>> <http://cr.openjdk.java.net/~ysuenaga/JDK-8164913/webrev.01/>
>>>>>
>>>>>
>>>>>     Yasumasa
>>>>>
>>>>>
>>>>>     On 2016/08/29 12:59, David Holmes wrote:
>>>>>
>>>>>         Hi Yasumasa,
>>>>>
>>>>>         On 28/08/2016 10:47 PM, Yasumasa Suenaga wrote:
>>>>>
>>>>>             Hi all,
>>>>>
>>>>>             If we try to attach invalid JVMTI agent via 
>>>>> JVMTI.agent_load
>>>>>             dcmd, we
>>>>>             will get
>>>>>             "Command executed successfully". However, it implies 
>>>>> error in
>>>>>             JVMTIAgentLoadDCmd.
>>>>>
>>>>>             This message is from JCmd.java when jcmd does not receive
>>>>>             output from
>>>>>             target VM.
>>>>>             So we should send error message from JVMTIAgentLoadDCmd.
>>>>>
>>>>>             I uploaded a webrev for it. Could you review it?
>>>>>
>>>>>
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8164913/webrev.00/
>>>>> <http://cr.openjdk.java.net/~ysuenaga/JDK-8164913/webrev.00/>
>>>>>
>>>>>
>>>>>         This seems reasonable.
>>>>>
>>>>>         src/share/vm/prims/jvmtiExport.cpp
>>>>>
>>>>>         This comment no longer matches the code and should be 
>>>>> deleted:
>>>>>
>>>>>         2412       // Agent_OnAttach executed so completion status 
>>>>> is JNI_OK
>>>>>         2413       st->print_cr("return code: %d", result);
>>>>>
>>>>>         Thanks,
>>>>>         David
>>>>>
>>>>>             I cannot access JPRT.
>>>>>             So I need a sponsor.
>>>>>
>>>>>
>>>>>             Thanks,
>>>>>
>>>>>             Yasumasa
>>>>>
>>