query_module: fix possbile NULL pointer dereference in knotd_mod_stats_free

diff --git a/src/knot/nameserver/query_module.c b/src/knot/nameserver/query_module.c
index 152c10b9306b198cf70da976255dd3b2f7ba1940..f93b810d60a7f5db9e7aa9a2b74b13e5190e8679 100644 (file)
--- a/src/knot/nameserver/query_module.c
+++ b/src/knot/nameserver/query_module.c
@@ -311,10 +311,11 @@ void knotd_mod_stats_free(knotd_mod_t *mod)
                return;
        }
 
-       unsigned threads = knotd_mod_threads(mod);
-
-       for (unsigned i = 0; i < threads; i++) {
-               free(mod->stats_vals[i]);
+       if (mod->stats_vals != NULL) {
+               unsigned threads = knotd_mod_threads(mod);
+               for (unsigned i = 0; i < threads; i++) {
+                       free(mod->stats_vals[i]);
+               }
        }
 
        free(mod->stats_vals);