move stream sync before free

Author: agray3

ggml/src/ggml-cuda/cpy.cu

@@ -350,8 +350,8 @@ static __global__ void cpy_q_f32(const char * cx, char * cdst_direct, const int
 void ggml_backend_dest_ptrs_copy(ggml_cuda_graph * cuda_graph, char ** host_dest_ptrs, const int host_dest_ptrs_size, cudaStream_t stream) {
 #if defined(GGML_CUDA_USE_GRAPHS) || defined(GGML_HIP_GRAPHS)
     if(cuda_graph->dest_ptrs_size < host_dest_ptrs_size) { // (re-)allocate GPU memory for destination pointers
-        if (cuda_graph->dest_ptrs_d != nullptr) cudaFree(cuda_graph->dest_ptrs_d);
         cudaStreamSynchronize(stream);
+        if (cuda_graph->dest_ptrs_d != nullptr) cudaFree(cuda_graph->dest_ptrs_d);
         cudaMalloc(&cuda_graph->dest_ptrs_d, host_dest_ptrs_size*sizeof(char *));
         cuda_graph->dest_ptrs_size = host_dest_ptrs_size;
     }