diff --git a/tools/libs/guest/xg_sr_save.c b/tools/libs/guest/xg_sr_save.c
index d74c72cba6..2ba7c3200c 100644
--- a/tools/libs/guest/xg_sr_save.c
+++ b/tools/libs/guest/xg_sr_save.c
@@ -809,7 +809,7 @@ static int setup(struct xc_sr_context *ctx)
         xch, dirty_bitmap, NRPAGES(bitmap_size(ctx->save.p2m_size)));
     ctx->save.batch_pfns = malloc(MAX_BATCH_SIZE *
                                   sizeof(*ctx->save.batch_pfns));
-    ctx->save.deferred_pages = calloc(1, bitmap_size(ctx->save.p2m_size));
+    ctx->save.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
 
     if ( !ctx->save.batch_pfns || !dirty_bitmap || !ctx->save.deferred_pages )
     {