RFR [8022584] Memory leak in some NetworkInterface methods

[Chris Hegarty]

Thanks for taking this Ivan.

Can you please make the changes suggested by both David and Alan ( 
simply return NULL/-1/JNI_FALSE, as appropriate, if GetStringUTFChars 
fails ( returns NULL ), then I will sponsor this change into jdk8 for you.

Please post an update webrev to cr.openjdk.java.net.

-Chris.

On 08/08/2013 06:01 AM, David Holmes wrote:
> Ivan,
>
> On 8/08/2013 2:05 PM, Ivan Gerasimov wrote:
>> David, Alan,
>>
>> I added checking for NULL  results and throwing OOMException if
>> necessary.
>
> You don't need to throw it yourself:
>
>    JNU_ThrowOutOfMemoryError(env, NULL);
>
> Assuming a correct VM implementation if NULL is returned then an OOME
> should already be pending and will be thrown as soon as your native code
> returns to Java.
>
> Thanks,
> David
>
>> I've also added some spaces along the code to improve indentation.
>>
>> Would you please review the updated webrev?
>> http://washi.ru.oracle.com/~igerasim/webrevs/8022584/1/webrev/
>>
>> Sincerely yours,
>> Ivan
>>
>>
>> On 08.08.2013 5:35, David Holmes wrote:
>>> On 8/08/2013 11:20 AM, Ivan Gerasimov wrote:
>>>> Thanks Alan!
>>>>
>>>> I've checked that and it turns out that GetStringUTFChars cannot return
>>>> NULL.
>>>> For allocation of the result string it calls AllocateHeap() with the
>>>> default EXIT_OOM fail strategy.
>>>> Thus, in case of being unable to allocate memory it simply stops VM.
>>>
>>> Ouch! That is a hotspot bug. GetStringUTFChars is supposed to throw
>>> OutOfMemoryError if it has memory issues, not abort the VM!
>>>
>>> I recommend that you check for NULL and/or a pending exception.
>>>
>>> David
>>>
>>>> Sincerely yours,
>>>> Ivan
>>>>
>>>> On 08.08.2013 5:05, Alan Bateman wrote:
>>>>> (cc'ing net-dev).
>>>>>
>>>>> The change looks okay to me. One suggestion (while you are there) is
>>>>> to check the return from  GetStringUTFChars so that the name returns
>>>>> when it fails with NULL.
>>>>>
>>>>> -Alan.
>>>>>
>>>>> On 07/08/2013 17:46, Ivan Gerasimov wrote:
>>>>>> Hello everybody!
>>>>>>
>>>>>> Some methods of NetworkInterface class were reported to leak memory.
>>>>>> http://bugs.sun.com/view_bug.do?bug_id=JDK-8022584 (not yet
>>>>>> available.)
>>>>>>
>>>>>> Examples are isUp() and isLoopback().
>>>>>>
>>>>>> Affected versions of jdk are 6, 7 and 8
>>>>>>
>>>>>> Would you please review a simple fix that removes the unnecessary
>>>>>> allocation?
>>>>>> http://cr.openjdk.java.net/~igerasim/8022584/0/webrev/
>>>>>>
>>>>>> Sincerely yours,
>>>>>> Ivan
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>