diff --git a/benchmarks/wasm/btree/2o1u.wat b/benchmarks/wasm/btree/2o1u.wat
index 1e55e025..8a4a2b80 100644
--- a/benchmarks/wasm/btree/2o1u.wat
+++ b/benchmarks/wasm/btree/2o1u.wat
@@ -1,4 +1,5 @@
 (module
+  (import "env" "log" (func $log (param i32)))
   (memory $0 2)
   (func $createBtree (param i32) (result i32) ;; createBtree(t), where t: degree of the btree
         (i32.const 0)
@@ -519,7 +520,7 @@
           )
         )
   ;; btreeInsertNonFull(x, k), where x: addr of a non full internal node; k: the key to insert
-  (func $btreeInsertNonFull (param i32) (param i32) (local i32)
+  (func $btreeInsertNonFull (param i32) (param i32) (local i32) (local $tmp i32)
         (local.get 0)     ;; x
         (i32.load offset=4)   ;; x.n
         (i32.const 1)
@@ -527,6 +528,9 @@
         (local.set 2)     ;; i = x.n -1
         (local.get 0)     ;; x
         (i32.load)        ;; get first i32 --> isLeaf
+        (local.tee $tmp)
+        (local.get $tmp)
+        (call $log)
         (i32.const 1)
         (i32.eq)        ;; is leaf?
         (if
@@ -2811,11 +2815,11 @@
         )
   (export "main" (func $main))
   (func $real_main
-    i32.const 1
+    i32.const 3
     i32.const 2
     i32.const 1
     call $main
   )
   (start $real_main)
-  (start $real_main)
+  (export "real_main" (func $real_main))
   )
diff --git a/benchmarks/wasm/btree/start.js b/benchmarks/wasm/btree/start.js
new file mode 100644
index 00000000..8104d9de
--- /dev/null
+++ b/benchmarks/wasm/btree/start.js
@@ -0,0 +1,19 @@
+const fs = require("fs");
+
+async function main() {
+  const bytes = fs.readFileSync("2o1u.wasm");
+  const env = { log: val => console.log(`logged ${val}`), };
+  const { instance } = await WebAssembly.instantiate(
+    bytes,
+    {
+      env: {
+        log(val) {
+          console.log(`log saw ${val}`);
+        }
+      }
+    }
+  );
+  instance.exports.real_main();
+  console.log(`finished`);
+}
+main();
\ No newline at end of file