diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 2036322..a99ac97 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -21,6 +21,9 @@ jobs:
         - '12'
         - '13'
         - '14'
+        - '15'
+        - '16'
+        - '17'
 
     steps:
     - uses: actions/checkout@v2
diff --git a/pg_auth_mon.c b/pg_auth_mon.c
index 4bdad3c..b534b6f 100644
--- a/pg_auth_mon.c
+++ b/pg_auth_mon.c
@@ -79,7 +79,7 @@ typedef struct auth_mon_rec
 #if PG_VERSION_NUM < 90400
 LWLockId	auth_mon_lock;
 #else
-LWLock	   *auth_mon_lock;
+static LWLock	   *auth_mon_lock;
 #endif
 
 /* Original Hook */