RFR(xs): 8181419: Race in jdwp invoker handling may lead to crashes or invalid results

[Thomas Stüfe]

Hi Sergey,

thank you for the review!

I ran jdi jtreg tests on both AIX and Linux x64, I had some issues but they
seemed preexisting (same issues without my patch). Could you please also
run tests you think are necessary on your platforms? Thanks!

best Regards, Thomas

On Wed, Jun 14, 2017 at 1:36 AM, serguei.spitsyn at oracle.com <
serguei.spitsyn at oracle.com> wrote:

> On 6/13/17 14:16, serguei.spitsyn at oracle.com wrote:
>
> Hi Thomas,
>
> The fix looks great to me.
>
>
> Forgot to say that the copyright comment need an update.
>
> Thanks,
> Serguei
>
>
> Thank you for identifying and fixing the problem!
>
> Thanks,
> Serguei
>
>
> On 6/13/17 06:55, Thomas Stüfe wrote:
>
> Ping... Anyone?
>
> On Thu, Jun 1, 2017 at 2:18 PM, Thomas Stüfe <thomas.stuefe at gmail.com>
> wrote:
>
>> Hi all,
>>
>> please take a look at this proposed fix for a theoretical race in the
>> jdwp library.
>>
>> Issue: https://bugs.openjdk.java.net/browse/JDK-8181419
>> webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8181419-
>> Race-in-jdwp-invoker-handling-may-lead-to-crashes-or-
>> invalid-results/webrev.00/webrev/
>>
>> In short, this is an addition to Severin's fix to the jdwp invoke
>> handling (https://bugs.openjdk.java.net/browse/JDK-8153711).
>>
>> We have a potential race condition where the delayed cleanup of the saved
>> returnvalue object reference and the exception reference (released
>> in deletePotentiallySavedGlobalRefs() ) may be overtaken by a new
>> request which populates the thread request structure anew. If this happens,
>> deletePotentiallySavedGlobalRefs() may actually release the return value
>> / exception references of the follow up request, if that one was already
>> processed.
>>
>> The solution I choose is safe and conservative. We still release both
>> references, but use the locally saved JNI references. We just avoid
>> accessing the thread local request structure after it has been cleared for
>> reuse. This keeps timing and locking behaviour unchanged.
>>
>> I am currently running jtreg tests for com/sun/jdi on AIX and Linux.
>>
>> Kind Regards, Thomas
>>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/serviceability-dev/attachments/20170614/7c40d783/attachment.html>