diff --git a/test/core/surface/completion_queue_test.cc b/test/core/surface/completion_queue_test.cc
index 82dbaed6dd6..9175196fa1a 100644
--- a/test/core/surface/completion_queue_test.cc
+++ b/test/core/surface/completion_queue_test.cc
@@ -78,7 +78,7 @@ TEST(GrpcCompletionQueueTest, TestNoOp) {
   grpc_cq_completion_type completion_types[] = {GRPC_CQ_NEXT, GRPC_CQ_PLUCK};
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   LOG_TEST("test_no_op");
 
   attr.version = 1;
@@ -97,7 +97,7 @@ TEST(GrpcCompletionQueueTest, TestPollsetConversion) {
   grpc_cq_polling_type polling_types[] = {GRPC_CQ_DEFAULT_POLLING,
                                           GRPC_CQ_NON_LISTENING};
   grpc_completion_queue* cq;
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
 
   LOG_TEST("test_pollset_conversion");
 
@@ -118,7 +118,7 @@ TEST(GrpcCompletionQueueTest, TestWaitEmpty) {
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
   grpc_completion_queue* cc;
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   grpc_event event;
 
   LOG_TEST("test_wait_empty");
@@ -145,7 +145,7 @@ TEST(GrpcCompletionQueueTest, TestCqEndOp) {
   grpc_cq_completion completion;
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   void* tag = create_test_tag();
 
   LOG_TEST("test_cq_end_op");
@@ -178,7 +178,7 @@ TEST(GrpcCompletionQueueTest, TestCqTlsCacheFull) {
   grpc_cq_completion completion;
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   void* tag = create_test_tag();
   void* res_tag;
   int ok;
@@ -219,7 +219,7 @@ TEST(GrpcCompletionQueueTest, TestCqTlsCacheEmpty) {
   grpc_completion_queue* cc;
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   void* res_tag;
   int ok;
 
@@ -246,7 +246,7 @@ TEST(GrpcCompletionQueueTest, TestShutdownThenNextPolling) {
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
   grpc_completion_queue* cc;
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   grpc_event event;
   LOG_TEST("test_shutdown_then_next_polling");
 
@@ -268,7 +268,7 @@ TEST(GrpcCompletionQueueTest, TestShutdownThenNextWithTimeout) {
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
   grpc_completion_queue* cc;
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   grpc_event event;
   LOG_TEST("test_shutdown_then_next_with_timeout");
 
@@ -294,7 +294,7 @@ TEST(GrpcCompletionQueueTest, TestPluck) {
   grpc_cq_completion completions[GPR_ARRAY_SIZE(tags)];
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   unsigned i, j;
 
   LOG_TEST("test_pluck");
@@ -348,7 +348,7 @@ TEST(GrpcCompletionQueueTest, TestPluckAfterShutdown) {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
   grpc_event ev;
   grpc_completion_queue* cc;
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
 
   LOG_TEST("test_pluck_after_shutdown");
 
@@ -372,7 +372,7 @@ TEST(GrpcCompletionQueueTest, TestCallback) {
   grpc_cq_completion completions[GPR_ARRAY_SIZE(tags)];
   grpc_cq_polling_type polling_types[] = {
       GRPC_CQ_DEFAULT_POLLING, GRPC_CQ_NON_LISTENING, GRPC_CQ_NON_POLLING};
-  grpc_completion_queue_attributes attr;
+  grpc_completion_queue_attributes attr = {};
   unsigned i;
   static gpr_mu mu, shutdown_mu;
   static gpr_cv cv, shutdown_cv;