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

[Frederic Parain]

Hi David,

Here's an updated version of the fix:
http://cr.openjdk.java.net/~fparain/8137035/webrev.02/

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;
>>>>>
>>