RFR(S): JDK-8137035 tests got EXCEPTION_STACK_OVERFLOW on Windows 64 bit

[David Holmes]

On 3/09/2016 1:20 AM, Frederic Parain wrote:
> Hi David,
>
> Here's an updated version of the fix:
> http://cr.openjdk.java.net/~fparain/8137035/webrev.02/

Thanks - looks good!

I do have wonder what the consequence of the "_thread_in_Java -> 
in_java" may have been ??

David
-----

> Regards,
>
> Fred
>
> On 09/01/2016 03:29 AM, David Holmes wrote:
>> On 31/08/2016 9:04 AM, Frederic Parain wrote:
>>> Hi David,
>>>
>>> On 08/29/2016 11:10 PM, David Holmes wrote:
>>>> Hi Fred,
>>>
>>>>>> While examining the thread state logic in the exception handler I
>>>>>> noticed some pre-existing bugs:
>>>>>>
>>>>>> 2506   if (exception_code == EXCEPTION_ACCESS_VIOLATION) {
>>>>>> 2507     JavaThread* thread = (JavaThread*) t;
>>>>>>
>>>>>> there is no check that t is in fact a JavaThread, or even that t is
>>>>>> non-NULL. Such checks occur slightly later:
>>>>>
>>>>> I've investigated this issue, and it is currently harmless.
>>>>> The casted pointer is only used to call a method requiring
>>>>> a JavaThread* pointer and the only usage of its argument it's
>>>>> a NULL check. Unfortunately, fixing this issue would require
>>>>> to modify the prototype of os::is_memory_serialize_page()
>>>>> and propagate the change across all platforms using it.
>>>>> It's a wider scope fix than JDK-8137035.
>>>>
>>>> I was only expecting you to move (if the scoping allows it, else copy)
>>>> the later:
>>>
>>> The scoping doesn't allow his move, and adding the test would
>>> potentially change the behavior (I'm expecting that only JavaThreads
>>> could be blocked on the serialization page, but I might be wrong).
>>
>> If we were to find that a non-JavaThread were executing that code that
>> would be a significant bug I think. I really think this needs to be
>> fixed to ensure it is a JavaThread - even if you only add an assert.
>>
>> Thanks,
>> David
>>
>>> Fred
>>>
>>>> if (t != NULL && t->is_Java_thread()) {
>>>>
>>>> check. ;)
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>>> I've added a comment the unsafe cast in os_windows.cpp file,
>>>>> highlighting the fact it was unsafe, and explaining why it
>>>>> is currently harmless.
>>>>>
>>>>>>
>>>>>> 2523   if (t != NULL && t->is_Java_thread()) {
>>>>>> 2524     JavaThread* thread = (JavaThread*) t;
>>>>>>
>>>