RFR (S) 8205608: Fix 'frames()' in ThreadReferenceImpl.c to prevent quadratic runtime behavior

[serguei.spitsyn at oracle.com]

Hi Ralf,

I think, you have to consider it reviewed.
Sorry, I was not clear no new webrev is needed.

Do you need a sponsor for the push?

Thanks,
Serguei


On 7/24/18 06:32, Schmelter, Ralf wrote:
> Hi all,
>
> here is the update webref with the fixed copyright: http://cr.openjdk.java.net/~simonis/webrevs/2018/8205608.v5/
>
> Best regards,
> Ralf
>
> -----Original Message-----
> From: serguei.spitsyn at oracle.com [mailto:serguei.spitsyn at oracle.com]
> Sent: Freitag, 20. Juli 2018 23:04
> To: Chris Plummer <chris.plummer at oracle.com>; Schmelter, Ralf <ralf.schmelter at sap.com>; serviceability-dev at openjdk.java.net; Stuefe, Thomas <thomas.stuefe at sap.com>
> Subject: Re: RFR (S) 8205608: Fix 'frames()' in ThreadReferenceImpl.c to prevent quadratic runtime behavior
>
> On 7/20/18 13:44, Chris Plummer wrote:
>> On 7/20/18 1:40 PM, serguei.spitsyn at oracle.com wrote:
>>> Hi Ralf,
>>>
>>>
>>> On 7/20/18 07:28, Schmelter, Ralf wrote:
>>>> Hi Sergue,
>>>>
>>>> I’ve updated the webref:
>>>> http://cr.openjdk.java.net/~simonis/webrevs/2018/8205608.v4/
>>> The copyright year in ThreadReferenceImpl.c still has to be 2018, not
>>> 2008.
>>>
>>> http://cr.openjdk.java.net/~simonis/webrevs/2018/8205608.v4/test/jdk/com/sun/jdi/Frames2Test.java.html
>>>
>>>
>>>    72             if (newDepth == -1_000) {
>>>    73                 // Pop some frames so there is room on the stack
>>> for the
>>>    74                 // call (including println()).
>>>    75                 notifyRecursionEnded();
>>>    76             }
>>>
>>>    I have a concern on potential issue mentioned in the comment above.
>>>    Should a StackOverflowError be expected here?
>>>
>>>    79         } catch (StackOverflowError e) {
>>>    80             // Use negative depth to indicate the recursion has
>>> ended.
>>>    81             return -1;
>>>    82         }
>>>
>>>    What is going to happen if the StackOverflowError was really caught
>>> above?
>> The SOE is really caught in the above code. I returns -1, and starts
>> the unwinding of the stack. After 1000 frames have been popped via
>> returns, notifyRecursionEnded() will be called. The pops are so
>> notifyRecursionEnded() can be called without worry of another SOE.
> Got it, thanks Chris.
>
> So, I'm Okay with the fix assuming the copyright year is fixed.
>
> Thanks,
> Serguei