diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index c70b04650c..f3ce174244 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -1594,6 +1594,8 @@ int cg_set_attribute(const char *controller, const char *path, const char *attri
         _cleanup_free_ char *p = NULL;
         int r;
 
+        assert(attribute);
+
         r = cg_get_path(controller, path, attribute, &p);
         if (r < 0)
                 return r;
@@ -1605,6 +1607,8 @@ int cg_get_attribute(const char *controller, const char *path, const char *attri
         _cleanup_free_ char *p = NULL;
         int r;
 
+        assert(attribute);
+
         r = cg_get_path(controller, path, attribute, &p);
         if (r < 0)
                 return r;