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

[Yasumasa Suenaga]

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.


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
>>>>
>