Safari plugin crashes on NPN_GetValue
static bool mainNPObjectInvoke(NPObject *obj, NPIdentifier identifier, const NPVariant *args, uint32_t argCount, NPVariant *result)
{
    printf("create main object");
    MainNPObject *mainObject = (MainNPObject *)obj;

    if (identifier == methodIdentifiers[METHOD_ID_GET_DEVICES])
    {
        NPObject *windowObj = NULL;
        browser->getvalue(mainObject->npp, NPNVWindowNPObject, &windowObj);
        // it crashed here
    ....
    }
}

NPObject *createMainNPObject(NPP npp)
{
    MainNPObject *object = (MainNPObject *)browser->createobject(npp, &mainNPClass);
    object->npp = npp;

    theMainObject = object;

    return (NPObject *)object;
}

NPError NPP_GetValue(NPP instance, NPPVariable variable, void *value)
{
    PluginObject *obj = instance->pdata;

    switch (variable) {
        case NPPVpluginCoreAnimationLayer:
            if (!obj->rootLayer)
                setupLayerHierarchy(obj);

            *(CALayer **)value = obj->rootLayer;

            return NPERR_NO_ERROR;

        case NPPVpluginScriptableNPObject:

            if (!obj->mainObject)
            {
                obj->mainObject = createMainNPObject(instance);
            }
 ....
}

static NPObject *mainNPObjectAllocate(NPP npp, NPClass *class)
{
    initializeIdentifiers();

    MainNPObject *mainObject = malloc(sizeof(MainNPObject));
    mainObject->deviceManager = [[DeviceManager alloc] init];

    return (NPObject *)mainObject;
}

typedef struct
{
    NPObject *npobject;
    NPP npp;
    DeviceManager *deviceManager;
} MainNPObject;

0x00007fff83f82dab  <+0019>  je     0x7fff83f82db9 <_ZN6WebKit14NetscapePlugin7fromNPPEP4_NPP+33>
0x00007fff83f82dad  <+0021>  incl   0x8(%rax)