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

[Schmelter, Ralf]

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