diff --git a/test/cpp/codegen/codegen_test_full.cc b/test/cpp/codegen/codegen_test_full.cc
index 2eacc99d8235737de790487d2b35d6876798e10e..98792bde047b93082dc2b9b9e8c0232f744b4c53 100644
--- a/test/cpp/codegen/codegen_test_full.cc
+++ b/test/cpp/codegen/codegen_test_full.cc
@@ -27,8 +27,8 @@ class CodegenTestFull : public ::testing::Test {};
 
 TEST_F(CodegenTestFull, Init) {
   grpc::CompletionQueue cq;
-  void* tag;
-  bool ok;
+  void* tag = nullptr;
+  bool ok = false;
   cq.AsyncNext(&tag, &ok, gpr_time_0(GPR_CLOCK_REALTIME));
   ASSERT_FALSE(ok);
 }