diff --git a/src/core/manager.h b/src/core/manager.h
index 4ab4231b3b9..92bfd489975 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -420,6 +420,7 @@ struct Manager {
 };
 
 static inline usec_t manager_default_timeout_abort_usec(Manager *m) {
+        assert(m);
         return m->default_timeout_abort_set ? m->default_timeout_abort_usec : m->default_timeout_stop_usec;
 }
 
diff --git a/src/core/service.h b/src/core/service.h
index 1b8df19771c..2aebc5f09d8 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -192,6 +192,7 @@ struct Service {
 };
 
 static inline usec_t service_timeout_abort_usec(Service *s) {
+        assert(s);
         return s->timeout_abort_set ? s->timeout_abort_usec : s->timeout_stop_usec;
 }