[Minor] Fix dns errors reporting

diff --git a/src/lua/lua_dns_resolver.c b/src/lua/lua_dns_resolver.c
index 7c224243e92b048f9282b095026ac613c9236810..061503f2d11df0e3a784da159f7c33a915337196 100644 (file)
--- a/src/lua/lua_dns_resolver.c
+++ b/src/lua/lua_dns_resolver.c
@@ -185,8 +185,12 @@ lua_dns_resolver_callback (struct rdns_reply *reply, gpointer arg)
        lua_pushboolean (L, reply->authenticated);
 
        if (lua_pcall (L, 6, 0, err_idx) != 0) {
-               msg_info_pool_check ("call to dns callback failed: %s", tb->str);
-               g_string_free (tb, TRUE);
+               tb = lua_touserdata (L, -1);
+
+               if (tb) {
+                       msg_info_pool_check ("call to dns callback failed: %s", tb->str);
+                       g_string_free (tb, TRUE);
+               }
        }
 
        lua_settop (L, err_idx - 1);