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From:   Cong Wang <xiyou.wangcong@gmail.com>
Date:   Tue, 25 Jun 2019 17:05:34 -0700
Message-ID: <CAM_iQpVT3dUKoZjeZDE3Mmk8C8OMtOE4_05Wq19C7VWDTQeSSw@mail.gmail.com>
Subject: Re: [PATCH net] net/sched: flower: fix infinite loop in fl_walk()
To:     Davide Caratti <dcaratti@redhat.com>
Cc:     Vlad Buslov <vladbu@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        Lucas Bates <lucasb@mojatatu.com>
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On Tue, Jun 25, 2019 at 12:29 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> On Tue, Jun 25, 2019 at 11:07 AM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> > On one hand, its callers should not need to worry about details
> > like overflow. On the other hand, in fact it does exactly what its
> > callers tell it to do, the problematic part is actually the
> > incremented id. On 64bit, it is fairly easy, we can just simply
> > know 'long' is longer than 32bit and leverage this to detect overflow,
> > but on 32bit this clearly doesn't work.
> >
> > Let me think about it.
>
> Davide, do you mind to try the attached patch?
>
> It should handle this overflow case more gracefully, I hope.

Well, it looks like it would miss UINT_MAX... Let me see how this
can be fixed.