Only touch ctx->priv if vp8_mmap_alloc succeeded.
diff --git a/vp8/vp8_dx_iface.c b/vp8/vp8_dx_iface.c
index e0e1103..36a0b39 100644
--- a/vp8/vp8_dx_iface.c
+++ b/vp8/vp8_dx_iface.c
@@ -223,11 +223,12 @@
         res = vp8_mmap_alloc(&mmap);
 
         if (!res)
+        {
             vp8_init_ctx(ctx, &mmap);
 
-        ctx->priv->alg_priv->defer_alloc = 1;
-        /*post processing level initialized to do nothing */
-
+            ctx->priv->alg_priv->defer_alloc = 1;
+            /*post processing level initialized to do nothing */
+        }
     }
 
     return res;