fix race condition when h < stride_h or w < stride_w (NVIDIA#562)

Co-authored-by: Haicheng Wu <haichengw@nvidia.com>

include/cutlass/conv/kernel/implicit_gemm_convolution_strided_dgrad.h

@@ -307,6 +307,26 @@ struct ImplicitGemmConvolutionStridedDgrad {
     int start_r, start_s;
     params.stride_w_divmod(start_r, start_s, filter_tile_m);
 
+    int filter_r = start_r;
+    int filter_s = start_s;
+
+    if (params.problem_size.mode == Mode::kConvolution) {
+      filter_r = (params.problem_size.R - 1 - filter_r);
+      filter_s = (params.problem_size.S - 1 - filter_s);
+    }
+
+    // Starting h, w positions for filter position in gemm_k=0
+    int start_h, start_w;
+    strided_dgrad_starting_coords(
+      params.problem_size,
+      params.stride_h_divmod, params.stride_w_divmod,
+      filter_r, filter_s,
+      start_h, start_w);
+
+    if (start_h >= params.problem_size.H || start_w >= params.problem_size.W) {
+      return;
+    }
+
     typename Mma::FragmentC accumulators;
 
     accumulators.clear();