diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 34a09d0fe5..518c48fd2c 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -341,7 +341,6 @@ stages:
 
 .unit_test_tsan: &unit_test_tsan_job
   <<: *unit_test_common
-  allow_failure: true
   after_script:
     - find lib -name 'tsan.*' -exec python3 util/parse_tsan.py {} \;
   artifacts:
diff --git a/lib/ns/tests/nstest.c b/lib/ns/tests/nstest.c
index bc421272aa..769bac28fb 100644
--- a/lib/ns/tests/nstest.c
+++ b/lib/ns/tests/nstest.c
@@ -107,6 +107,8 @@ __wrap_isc_nmhandle_detach(isc_nmhandle_t **handlep) {
 	ns_client_t *client = (ns_client_t *)handle;
 	int i;
 
+	*handlep = NULL;
+
 	for (i = 0; i < 32; i++) {
 		if (atomic_load(&client_addrs[i]) == (uintptr_t)client) {
 			break;
@@ -122,7 +124,6 @@ __wrap_isc_nmhandle_detach(isc_nmhandle_t **handlep) {
 		isc_mem_put(mctx, client, sizeof(ns_client_t));
 	}
 
-	*handlep = NULL;
 	return;
 }