From: Eric Dumazet <eric.dumazet@gmail•com>
To: Francesco Ruggeri <fruggeri@arista•com>
Cc: David Miller <davem@davemloft•net>,
netdev <netdev@vger•kernel.org>,
Francesco Ruggeri <fruggeri@aristanetworks•com>,
Willem de Bruijn <willemb@google•com>
Subject: Re: [PATCH net] net/packet: fix a race in packet_bind() and packet_notifier()
Date: Tue, 28 Nov 2017 07:13:01 -0800 [thread overview]
Message-ID: <1511881981.16595.13.camel@gmail.com> (raw)
In-Reply-To: <CA+HUmGh4CGPOmDDAkRy165NTf9PDQkBEY2Da41VZFoVZBBBHxQ@mail.gmail.com>
On Tue, 2017-11-28 at 02:23 -0800, Francesco Ruggeri wrote:
> On Mon, Nov 27, 2017 at 8:00 PM, Eric Dumazet <eric.dumazet@gmail•com
> > wrote:
> > From: Eric Dumazet <edumazet@google•com>
> >
> >
...
> > +++ b/net/packet/af_packet.c
> > @@ -336,7 +336,7 @@ static void register_prot_hook(struct sock *sk)
> > {
> > struct packet_sock *po = pkt_sk(sk);
> >
> > - if (!po->running) {
> > + if (!po->running && !po->frozen) {
>
> Would it make sense to move the check for po->frozen to
> packet_notifier(NETDEV_UP)?
> As far as I can tell that is the only case today that can cause this
> race condition, and if new cases come up in the future an error code
> may be required rather than silently turning register_prot_hook()
> into
> a noop.
> Otherwise it looks fine to me.
>
Whatever works for me is fine, I have no strong opinion on this.
Note that frozen is only set in the case we know that
register_prot_hook() is going to be called by us.
next prev parent reply other threads:[~2017-11-28 15:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-28 4:00 [PATCH net] net/packet: fix a race in packet_bind() and packet_notifier() Eric Dumazet
2017-11-28 10:23 ` Francesco Ruggeri
2017-11-28 15:13 ` Eric Dumazet [this message]
2017-11-28 14:48 ` David Miller
2017-11-28 15:14 ` Eric Dumazet
2017-11-28 16:03 ` [PATCH v2 " Eric Dumazet
2017-11-28 16:14 ` David Miller
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