diff --git a/vp8/common/alloccommon.c b/vp8/common/alloccommon.c
index 369d48101929dad946083ae545ae9e1196835f33..3fcc3088c2c0b9d0b48b4a124b32777c62228f67 100644
--- a/vp8/common/alloccommon.c
+++ b/vp8/common/alloccommon.c
@@ -24,7 +24,7 @@ extern  void vp8_init_scan_order_mask();
 void vp8_update_mode_info_border(MODE_INFO *mi, int rows, int cols)
 {
     int i;
-    vpx_memset(mi - cols - 1, 0, sizeof(MODE_INFO) * cols + 1);
+    vpx_memset(mi - cols - 2, 0, sizeof(MODE_INFO) * (cols + 1));
 
     for (i = 0; i < rows; i++)
     {