PING: RFR: 8205992: jhsdb cannot attach to Java processes running in Docker containers

[Yasumasa Suenaga]

Hi Chris,

Thank you for your comment.
I uploaded new webrev. Could you review again?

  http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.02/

I tested my change on Linux x64, but I cannot check it on other
platform (includes older Linux).
However SA tests are included in HotSpot tier 1 tests. Tests on submit
repo work fine with this change
(mach5-one-ysuenaga-JDK-8205992-20180720-0305-31840).


Thanks,

Yasumasa


2018-07-20 3:26 GMT+09:00 Chris Plummer <chris.plummer at oracle.com>:
> Hi Yasumasa,
>
>   84     // It maps the LWPID in the host to it in the container.
>
> "it" -> "the PID"
>
>  286     // Get LWPID in the host from the container's LWPID.
>  287     public int getHostPID(int id) {
>  288         try {
>  289             return nspidMap.get(id);
>  290         } catch (NullPointerException e) {
>  291             return -1;
>  292         }
>  293     }
>
> What is the source of the NPE here? Is it because nspidMap was never
> initialized because the process is not in a container? In that case I think
> you should be checking for null rather than having an NPE be part of normal
> execution.
>
>   42             int hostPID =
> ((LinuxDebuggerLocal)debugger).getHostPID(pid);
>   43             if (hostPID != -1) {
>   44                 pid = hostPID;
>   45             }
>
> A comment here would be helpful.
>
> The rest looks good. I should probably run it through some internal testing.
> Let me know when you have a final webrev.
>
> thanks,
>
> Chris
>
>
> On 7/18/18 5:59 AM, Yasumasa Suenaga wrote:
>>
>> PING:
>>
>> Could you review it?
>>
>>    JBS:    https://bugs.openjdk.java.net/browse/JDK-8205992
>>    webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.01/
>>
>> This change has been reviewed by Jini.
>> We need a Reviewer.
>>
>>
>> Thanks,
>>
>> Yasumasa
>>
>>
>> On 2018/07/12 13:42, Yasumasa Suenaga wrote:
>>>
>>> Thanks Jini,
>>>
>>> I uploaded new webrev. It contains some comments and removing extra
>>> space.
>>>
>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.01/
>>>
>>>
>>> Yasumasa
>>>
>>>
>>>
>>> 2018-07-12 2:32 GMT+09:00 Jini George <jini.george at oracle.com>:
>>>>
>>>> Hi Yasumasa,
>>>>
>>>> This looks good to me except for one nit. And some more comments would
>>>> help.
>>>> For e.g., it would help to say that NSPidMap is to map the host to
>>>> container
>>>> lwpids.
>>>>
>>>> The nit:
>>>>
>>>> *
>>>>
>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.00/src/jdk.hotspot.agent/linux/native/libsaproc/LinuxDebuggerLocal.c.sdiff.html
>>>> Line 253: extra space after the parentheses
>>>>
>>>> Thanks,
>>>> Jini.
>>>>
>>>> On 7/4/2018 4:34 AM, Yasumasa Suenaga wrote:
>>>>>
>>>>>
>>>>> PING: Could you review it?
>>>>>
>>>>>>    JBS: https://bugs.openjdk.java.net/browse/JDK-8205992
>>>>>>    webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.00/
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa
>>>>>
>>>>>
>>>>> On 2018/06/28 22:12, Yasumasa Suenaga wrote:
>>>>>>
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> Please review this change.
>>>>>>
>>>>>>    JBS: https://bugs.openjdk.java.net/browse/JDK-8205992
>>>>>>    webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8205992/webrev.00/
>>>>>>
>>>>>> I tried to attach jhsdb to java process in docker container from
>>>>>> container host, but it couldn't.
>>>>>> jcmd supports PID namespace in JDK-8193710, but jhsdb hasn't yet.
>>>>>>
>>>>>> SA gets LWP ID via thread stack and funcs in libthread_db.so, but they
>>>>>> returns PIDs in container - they are different from host's PID. So I
>>>>>> added
>>>>>> the code to scan /proc/<PID>/task to get all LWP IDs and they are kept
>>>>>> in a
>>>>>> Map in LinuxDebuggerLocal.
>>>>>>
>>>>>> Also SA_ALTROOT is set to /proc/<PID>/root if SA detects debuggee runs
>>>>>> in
>>>>>> container. It helps SA to parse binaries in container.
>>>>>>
>>>>>> This change has been pushed to submit repo, and it was failed on OS X
>>>>>> (mach5-one-ysuenaga-JDK-8205992-20180628-1015-28963).
>>>>>> But I guess it causes JDK-8205906. This change affects to Linux only.
>>>>>>
>>>>>> Could you review it?
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>
>
>