RFR 9: 8133552 : java/lang/ProcessHandle/InfoTest.java fails intermittently - incorrect user

[Volker Simonis]

Hi Roger,

looks good now.

Thanks,
Volker


On Thu, Sep 10, 2015 at 7:03 PM, Roger Riggs <Roger.Riggs at oracle.com> wrote:
> Hi Volker,
>
> Thanks for the review, I added the code you provided to use the correct
> length.
>
> Updated the webrev:
>     http://cr.openjdk.java.net/~rriggs/webrev-info-8133552/
>
> Roger
>
>
>
> On 9/10/2015 11:52 AM, Volker Simonis wrote:
>
> On Wed, Sep 9, 2015 at 11:49 PM, Roger Riggs <Roger.Riggs at oracle.com> wrote:
>
> Hi,
>
> Please review this update to extract the uid on from the owner of the
> /proc/<pid> file.
> It should be more reliable than using the owner of the /proc/<pid>/cmdline
> file.
>
> Webrev:
>     http://cr.openjdk.java.net/~rriggs/webrev-info-8133552/
>
> Hi Roger,
>
> the change looks good. I've only found one little problem:
>
> In:
>
> strncat(fn, "/cmdline", sizeof fn);
>
> 'fn' is not empty any more, so I think it should read:
>
> strncat(fn, "/cmdline", sizeof fn - strnlen(fn, sizeof fn) - 1);
>
> Also, increasing the timeout to 30 sec is reasonable.
>
> Thank you and best regards,
> Volker
>
> Thanks, Roger
>
>
>
> On 9/9/2015 12:56 PM, Roger Riggs wrote:
>
> Hi Volker,
>
> Thanks for the review and diagnosis.
>
> Can opening /proc/pid be used as a fallback if the st_uid is zero or
> is it worth the overhead of stat'ing /proc/pid always?
>
> Thanks, Roger
>
>
> On 9/9/2015 11:46 AM, Volker Simonis wrote:
>
> Hi Roger,
>
> I think your change looks good and it surely improves the test
> stability but I don't think it solves the problem in all cases.
>
> I think this problem is caused by a <defunct> (i.e. "zombie") process
> (the spawned process lived too short and was already a zombie when the
> info object was created). If you look at the proc-file system entry of
> a <defunct> process you can see that its 'cmdline' file has zero size
> and the file is owned by root. This is exactly what is reported by the
> corresponding info object in the bug report (user=root and no cmd
> field).
>
> We may need to improve the way how we get the uid of a pid on Linux.
> The current way of querying the owner of /proc/<pid>/cmdline seems to
> be unreliable. We may instead take the owner of /proc/<pid> which
> seems to be still the initial user of the process.
>
> Regards,
> Volker
>
>
> On Tue, Sep 8, 2015 at 11:35 PM, Roger Riggs <Roger.Riggs at oracle.com>
> wrote:
>
> With link to webrev corrected:
>
> On 9/8/2015 5:08 PM, Roger Riggs wrote:
>
> Please review an intermittent test bug fix.
> The test setup time is very short and the user may be returned as 0
> which
> is reported as root.
> The correction lengthens the time allowed for the process to start.
>
> The test is removed from the ProblemList.
>
> Webrev:
>     http://cr.openjdk.java.net/~rriggs//webrev-info-8133552
>
> Bug:
>    https://bugs.openjdk.java.net/browse/JDK-8133552
>
> Thanks, Roger
>
>