Fix CudaNdarray view of view on something else then CudaNdarray.

theano/misc/tests/test_pycuda_theano_simple.py

@@ -71,6 +71,14 @@ def test_pycuda_memory_to_theano():
     print "gpuarray ref count after creating a CudaNdarray", sys.getrefcount(y)
     assert sys.getrefcount(y)==3
     assert (numpy.asarray(z) == 0).all()
+    assert z.base is y
+
+    # Test that we can take a view from this cuda view on pycuda memory
+    zz = z.view()
+    assert sys.getrefcount(y) == 4
+    assert zz.base is y
+    del zz
+    assert sys.getrefcount(y) == 3
 
     cuda_ones = cuda_ndarray.CudaNdarray(numpy.asarray([[[1]]],dtype='float32'))
     z += cuda_ones

theano/sandbox/cuda/cuda_ndarray.cu

@@ -2585,14 +2585,11 @@ int CudaNdarray_set_device_data(CudaNdarray * self, float * data, PyObject * bas
     // Get the original base object (base.base.base...)
     PyObject * orig_base = base;
     // base is not always a CudaNdarray. It can be a GpuArray from pycuda, ...
-    if (orig_base && CudaNdarray_Check(orig_base))
-    {
-        while (((CudaNdarray*) orig_base)->base)
+    while (orig_base && CudaNdarray_Check(orig_base) && ((CudaNdarray*) orig_base)->base)
     {
         // base_base is itself a view
         orig_base = ((CudaNdarray*) orig_base)->base;
     }
-    }
     //N.B. XDECREF and XINCREF are no-ops for NULL pointers
     if (self->base != orig_base)
     {