diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index 1c2ac81353..e51ab1cd19 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -669,9 +669,12 @@ int user_get_idle_hint(User *u, dual_timestamp *t) {
         return idle_hint;
 }
 
-int user_check_linger_file(User *u) {
+int user_check_linger_file(const User *u) {
         _cleanup_free_ char *cc = NULL;
-        char *p = NULL;
+        const char *p;
+
+        assert(u);
+        assert(u->user_record);
 
         cc = cescape(u->user_record->user_name);
         if (!cc)
diff --git a/src/login/logind-user.h b/src/login/logind-user.h
index 7b10c4fd60..5c82f490f2 100644
--- a/src/login/logind-user.h
+++ b/src/login/logind-user.h
@@ -82,7 +82,7 @@ int user_get_idle_hint(User *u, dual_timestamp *t);
 int user_save(User *u);
 int user_load(User *u);
 int user_kill(User *u, int signo);
-int user_check_linger_file(User *u);
+int user_check_linger_file(const User *u);
 void user_elect_display(User *u);
 void user_update_last_session_timer(User *u);