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From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Tue, 13 Dec 2016 16:19:01 -0800
Message-ID: <CAM_iQpVFkNdEirvBDi8wV=iExt9BnCm3KU7+Q8oqhrJJtcnu9Q@mail.gmail.com>
Subject: Re: [RFC PATCH v3] audit: use proper refcount locking on audit_sock
To: Richard Guy Briggs <rgb@redhat.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, linux-audit@redhat.com,
        Dmitry Vyukov <dvyukov@google.com>, Eric Dumazet <edumazet@google.com>,
        Eric Paris <eparis@redhat.com>, Paul Moore <pmoore@redhat.com>,
        sgrubb@redhat.com
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On Tue, Dec 13, 2016 at 7:03 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
> @@ -1283,8 +1299,10 @@ static void __net_exit audit_net_exit(struct net *net)
>  {
>         struct audit_net *aunet = net_generic(net, audit_net_id);
>         struct sock *sock = aunet->nlsk;
> +       mutex_lock(&audit_cmd_mutex);
>         if (sock == audit_sock)
>                 auditd_reset();
> +       mutex_unlock(&audit_cmd_mutex);

This still doesn't look correct to me, b/c here we release the audit_sock
refcnt twice:

1) inside audit_reset()
2) netlink_kernel_release()