fix StridedNumelCopyWithAxis

Author: typhoonzero

paddle/fluid/operators/strided_memcpy.h

@@ -58,6 +58,7 @@ inline void StridedNumelCopyWithAxis(const platform::DeviceContext& ctx,
   int64_t before = dst_stride_numel[0] / dst_stride_numel[axis];
   int64_t src_after = src_stride_numel[axis];
   int64_t dst_after = dst_stride_numel[axis];
+  int64_t copy_size = std::min(src_after, dst_after);
   auto place = ctx.GetPlace();
 
   PADDLE_ENFORCE_EQ(src_stride_numel.size(), dst_stride_numel.size(),
@@ -82,14 +83,14 @@ inline void StridedNumelCopyWithAxis(const platform::DeviceContext& ctx,
     if (platform::is_cpu_place(place)) {
       auto& cpu_place = boost::get<platform::CPUPlace>(place);
       memory::Copy(cpu_place, dst + i * dst_after, cpu_place,
-                   src + i * src_after, sizeof(T) * src_after);
+                   src + i * src_after, sizeof(T) * copy_size);
     } else {
 #ifdef PADDLE_WITH_CUDA
       auto& gpu_place = boost::get<platform::CUDAPlace>(place);
       auto& cuda_ctx =
           reinterpret_cast<const platform::CUDADeviceContext&>(ctx);
       memory::Copy(gpu_place, dst + i * dst_after, gpu_place,
-                   src + i * src_after, sizeof(T) * src_after,
+                   src + i * src_after, sizeof(T) * copy_size,
                    cuda_ctx.stream());
 #else
       PADDLE_THROW("Paddle is not compiled with GPU");