JVM crash by creating VarHandle

[Maurizio Cimadamore]

I guess what I was trying to assess was as to whether a straight call to 
MemoryHandles.varhandle would crash with exception. It seems that's not 
the case (in fact all our tests pass, and I tried several example just 
now, which work).

I will take a look at the links you provided - given this involves 
interacting with a native library, there's an actual possibility that 
some _previous_ operation ended up corrupting the VM memory state, which 
then shows up in some weird form.

Maurizio


On 01/02/2020 23:26, Ty Young wrote:
>
> On 2/1/20 5:09 PM, Maurizio Cimadamore wrote:
>>
>> On 01/02/2020 23:01, Ty Young wrote:
>>>
>>> On 2/1/20 4:49 PM, Maurizio Cimadamore wrote:
>>>>
>>>> On 01/02/2020 12:31, Ty Young wrote:
>>>>> MemoryHandles.varHandle(long.class, ByteOrder.nativeOrder()); 
>>>> Hi Ty,
>>>> thanks for reaching out - I assume you are on the foreign-jextract 
>>>> branch?
>>>
>>>
>>> Yep. The build is right after the name() method was added to SystemABI.
>>>
>>>
>>>> And also, is the above snippet enough to reproduce the crash for 
>>>> you? Or does it only happen sometimes, but not others?
>>>
>>>
>>> It seems to only happen when accessing the struct field from a 
>>> struct that resides in memory. Never outside of an array.
>>>
>>>
>>> Here is a Github Gist, if it helps any: 
>>> https://gist.github.com/BlueGoliath/307f60856afee04e218b759420a53fb7
>>
>> The stack trace you showed seems to point at a constructor somewhere:
>>
>>  org.goliath.crosspoint.fields.NumberField.<init>
>>
>> so, the crash  seems to happen outside of memory access - e.g. it 
>> happens on actual var handle creation. So I assume that the thing 
>> which actually fails is this?
>>
>> https://github.com/BlueGoliath/Crosspoint/blob/master/src/main/java/org/goliath/crosspoint/fields/NumberField.java#L29 
>>
>
>
> Yep.
>
>
>>
>> Is there a repeatable way to call the NumberField constructor which 
>> will lead to the crash?
>
>
> Got a Linux machine that has an Nvidia GPU? I've pushed local code to 
> Github. The bindings I'm working on right now are here:
>
>
> https://github.com/BlueGoliath/GoliathBindings
>
>
> I have a test class for testing the bindings within it, which shows 
> the problem:
>
>
> https://github.com/BlueGoliath/GoliathBindings/blob/master/modules/org.goliath.bindings.nvml/src/main/java/org/goliath/bindings/nvml/main/Test.java 
>
>
>
> You can get the bindings to work on Windows(since NVML is 
> cross-platform) but you'll have to add the library to the path and 
> change the name string in nvml_h.java. I think it's just nvml.dll in 
> Windows.
>
>
>>
>> Maurizio
>>
>>>
>>>
>>>
>>>>
>>>> Thanks
>>>> Maurizio
>>>>