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Date:      Tue, 18 Jul 2017 18:04:24 -0700
From:      Vincenzo Maffione <v.maffione@gmail.com>
To:        Luiz Otavio O Souza <lists.br@gmail.com>
Cc:        Marius Strobl <marius@freebsd.org>, hps@freebsd.org, ae@freebsd.org,  FreeBSD Net <freebsd-net@freebsd.org>, "Eggert, Lars" <lars@netapp.com>
Subject:   Re: NULL pointer dereference bug triggered by netmap
Message-ID:  <CA%2B_eA9hUaoJ=qLoqDDyx-8cbs%2BiZeoXUWR%2BvOjgZ0VqtusyCTw@mail.gmail.com>
In-Reply-To: <CAB=2f8zaFmF_mW3wq_zgp9R47_X4Q%2B=1c53qStUFm=vM8rRwXA@mail.gmail.com>
References:  <CA%2B_eA9goJ6j=q6UO-%2BfOt-aHVgFmujQfH8WfYEHf9=PQobdwHg@mail.gmail.com> <20170705110512.GA28058@alchemy.franken.de> <CA%2B_eA9h138BhHaeyEojzM3UFc__GWxV72uVSHCWVWw-6CbnGsw@mail.gmail.com> <20170711200510.GB60651@alchemy.franken.de> <CA%2B_eA9jC6WFDk-96XDzCEZqea2_E3N8eL9_fHvevtVLXU40dHg@mail.gmail.com> <CAB=2f8zaFmF_mW3wq_zgp9R47_X4Q%2B=1c53qStUFm=vM8rRwXA@mail.gmail.com>

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Hi,
  Looks good to me, although I'm not sure whether if_transmit should
assert(mbuf == NULL). Couldn't we just drop the mbuf if we receive it?

Thanks,
  Vincenzo

2017-07-18 10:43 GMT-07:00 Luiz Otavio O Souza <lists.br@gmail.com>:

> On 12 July 2017 at 02:19, Vincenzo Maffione wrote:
> > Yes.
> >
> > Actually, we would also need one beteween the following two options:
> > 1) Implementing a dummy if_start() for if_loop.c
> > 2) Prevent netmap from using if_loop.
>
> Hi,
>
> Please, check the attached patches.
>
> Luiz
>
> >
> > 2017-07-11 22:05 GMT+02:00 Marius Strobl <marius@freebsd.org>:
> >
> >> On Thu, Jul 06, 2017 at 02:19:42PM -0700, Vincenzo Maffione wrote:
> >> > Sure, can anyone commit this?
> >>
> >> The addition of KASSERTs like the below one to if_handoff() and
> >> if_start()? Sure.
> >>
> >> Marius
> >>
> >> >
> >> > Il 5 lug 2017 4:05 AM, "Marius Strobl" <marius@freebsd.org> ha
> scritto:
> >> >
> >> > > On Mon, Jul 03, 2017 at 05:08:09PM +0200, Vincenzo Maffione wrote:
> >> > > > Details here:
> >> > > >
> >> > > > https://github.com/luigirizzo/netmap/issues/322
> >> > > >
> >> > > > Is it acceptable to commit the proposed patch?
> >> > >
> >> > > As suggested by hselasky@, the outliner problem at hand is better
> >> solved
> >> > > by a dummy if_start method in order to not hurt the fast-path.
> Thus, if
> >> > > anything at all, a KASSERT(ifp->if_start != NULL, "no if_start
> method")
> >> > > should be added to if_handoff() and if_start().
>



-- 
Vincenzo Maffione



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