RFR: 8178784: Revisit changes for making Serviceability Agent attach functionality optional

Jini George jini.george at oracle.com
Wed May 31 14:59:02 UTC 2017

Hi Poonam,

No, the corefile attaching does not work yet. I am working on enabling 


On 5/31/2017 12:55 AM, Poonam Parhar wrote:
> Hello Jini,
> Thanks for making these changes.
> Does the core file attaching also work with these changes?
> Thanks,
> Poonam
>> -----Original Message-----
>> From: Jini George
>> Sent: Monday, May 29, 2017 1:31 AM
>> To: Mikael Vidstedt
>> Cc: portola-dev at openjdk.java.net
>> Subject: Re: RFR: 8178784: Revisit changes for making Serviceability
>> Agent attach functionality optional
>> Thanks much for the review, Mikael.
>> The modified webrev is at:
>> http://cr.openjdk.java.net/~jgeorge/8178784/webrev.01/index.html
>> I have shifted the logic of reading in the /proc/<pid>/task/ entries to
>> read_thread_info in libproc_impl.c, and ps_core.c is more or less
>> intact except for the strerror_r related correction. I have removed the
>> extra spaces between the function name and the parenthesis also.
>> Thanks,
>> Jini.
>> On 5/25/2017 11:57 PM, Mikael Vidstedt wrote:
>>> Jini,
>>> Thanks a lot for looking into this! The changes look good. One
>> question:
>>> Would it be possible to implement the whole opendir/readdir/closedir
>> walk as an alternative implementation of read_thread_info in
>> libproc_impl.c instead? Without having tried it, I think that would
>> mean you can revert the whole ps_core.c file back to what it was before
>> I added the #include guards, and all the special logic will instead be
>> in libproc_impl.c.
>>> Minor nit: there are a few places where you have a space between the
>> function name and the parenthesis (after readdir for example), which
>> doesn’t seem to be the style used in the rest of the places in the SA.
>>> Cheers,
>>> Mikael
>>>> On May 25, 2017, at 5:26 AM, Jini George <jini.george at oracle.com>
>> wrote:
>>>> Hi all,
>>>> Please review the changes for enabling live debugging (attaching to
>> a process) with SA on Alpine Linux.
>>>> Webrev: http://cr.openjdk.java.net/~jgeorge/8178784/webrev.00/
>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8178784
>>>> The crux of the changes are:
>>>> 1. To include the functions #ifdef-ed out by INCLUDE_SA_ATTACH, and
>> to correct build errors resulting due to the inclusion of these
>> functions.
>>>> 2. SA on Linux uses the thread_db library for attach debugging. This
>> library is not available on Alpine Linux. So instead of relying on
>> thread_db, I have made changes to iterate over the list of tasks in the
>> /proc/<pid>/task directory to find the list of threads to ptrace attach
>> to. This enables the jhsdb commands like threads, jstack etc.
>>>> Thanks,
>>>> Jini.

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