From mboxrd@z Thu Jan  1 00:00:00 1970
From: Craig Gallek <kraigatgoog@gmail.com>
Subject: Re: Uninitialized value in __sk_nulls_add_node_rcu()
Date: Tue, 5 Dec 2017 14:39:04 -0500
Message-ID: <CAEfhGiwQe-whM8p1OuLC3WntogmC6AeLS0HPRUcTL85ii8hKmw@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Cc: Eric Dumazet <edumazet@google.com>,
        Alexander Potapenko <glider@google.com>,
        David Miller <davem@davemloft.net>,
        Networking <netdev@vger.kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-qt0-f177.google.com ([209.85.216.177]:42555 "EHLO
        mail-qt0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751990AbdLETjI (ORCPT
        <rfc822;netdev@vger.kernel.org>); Tue, 5 Dec 2017 14:39:08 -0500
Received: by mail-qt0-f177.google.com with SMTP id g9so3524602qth.9
        for <netdev@vger.kernel.org>; Tue, 05 Dec 2017 11:39:07 -0800 (PST)
Received: from mail-qt0-f177.google.com (mail-qt0-f177.google.com. [209.85.216.177])
        by smtp.gmail.com with ESMTPSA id z8sm515145qta.81.2017.12.05.11.39.05
        for <netdev@vger.kernel.org>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Tue, 05 Dec 2017 11:39:06 -0800 (PST)
Received: by mail-qt0-f177.google.com with SMTP id g9so3524294qth.9
        for <netdev@vger.kernel.org>; Tue, 05 Dec 2017 11:39:05 -0800 (PST)
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Tue, Dec 5, 2017 at 9:18 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> On Tue, 2017-12-05 at 06:15 -0800, Eric Dumazet wrote:
>>
>> +     hlist_nulls_add_head_rcu(&sk->sk_nulss_node, list);
>
> Typo here, this needs sk_nulls_node of course.
>

Thanks Eric, this looks good to me.  The tail insertion is still
required in udp_lib_get_port for the second layer hash, but not here.
fwiw, reuseport_dualstack in the selftests directory verifies this
behavior.  I tried it with your patch (it still passes) and removing
the udp_lib_get_port path (to make sure it breaks when it should).

Craig