RFR (S): 8230850: Test sun/tools/jcmd/TestProcessHelper.java fails intermittently

[Thomas Stüfe]

Hi Christoph,

in general I think this is fine. The increase-by-pow2 sleep time is odd but
okay :)

The whole things seems rather fragile and has a lot of question marks but I
think your fix does not make it worse. One fun error now is that with a
follow up java test reusing the PID we could get a wrong main class but I
think the chances are astronomically low.

Only remark, you fix this in the platform shared code, if this is a Linux
only issue maybe it should be fixed
in /shared/projects/openjdk/jdk-jdk/source/src/jdk.jcmd/linux/classes/sun/tools/ProcessHelper.java
instead? If not, I would remove at least the /proc/<pid>/cmdline comment
since this is quite platform specific.

Cheers, Thomas


On Wed, Sep 11, 2019 at 2:39 PM Langer, Christoph <christoph.langer at sap.com>
wrote:

> Hi,
>
>
>
> please review this change for test sun/tools/jcmd/TestProcessHelper.java
> to make it more robust.
>
>
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8230850
>
> Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8230850.0/
>
>
>
> This Linux only test is starting several Java processes and then tries to
> figure out the main class by invoking jdk.jcmd's linux specific
> ProcessHelper implementation which parses the contents of
> /proc/<pid>/cmdline.
>
> Under some circumstances, the test already attempts to read
> /proc/<pid>/cmdline before it actually exists or is filled with data. This
> can be fixed with some sleeps/retries to wait for that data to be ready.
>
> In the actual jcmd tool, such behavior of ProcessHelper. getMainClass
> should not be an issue because it is handled in ProcessArgumentMatcher [0].
>
>
>
> Thanks
>
> Christoph
>
>
>
> [0]
> http://hg.openjdk.java.net/jdk/jdk/file/8b08eaf9a0eb/src/jdk.jcmd/share/classes/sun/tools/common/ProcessArgumentMatcher.java#l86
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.java.net/pipermail/serviceability-dev/attachments/20190911/624fd549/attachment-0001.html>