From: Cong Wang <xiyou.wangcong@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@toke.dk>
Cc: "Linux Kernel Network Developers" <netdev@vger.kernel.org>,
"Cake List" <cake@lists.bufferbloat.net>,
"Toke Høiland-Jørgensen" <toke@redhat.com>
Subject: Re: [Cake] [PATCH 1/4] sched: Avoid dereferencing skb pointer after child enqueue
Date: Thu, 10 Jan 2019 10:16:01 -0800 [thread overview]
Message-ID: <CAM_iQpUB8v-xN6gmeKpt9BfdQCX6jR5Og6rqL=8EAsj1cNNNxw@mail.gmail.com> (raw)
In-Reply-To: <871s5muu25.fsf@toke.dk>
On Wed, Jan 9, 2019 at 12:14 AM Toke Høiland-Jørgensen <toke@toke.dk> wrote:
>
> Cong Wang <xiyou.wangcong@gmail.com> writes:
>
> > On Mon, Jan 7, 2019 at 11:50 AM Toke Høiland-Jørgensen <toke@toke.dk> wrote:
> >> @@ -1254,7 +1256,7 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
> >> if (cl->qdisc->q.qlen != 1) {
> >> if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) &&
> >
> >
> > Isn't this comparison problematic too? While you are on it...
>
> Well, I was only looking at safety issues, and since it's not
> dereferencing the pointer, that's not really an issue here. The check is
> just going to always fail if GSO splitting is enabled. Which I'm not
> actually sure is an error in this case?
Yeah, I knew you only fix defereferences. The comparison is used
to check if the enqueued packet is the head of the queue, which
is incorrect to me for GSO splitting case. Don't worry, we can fix it later.
next prev parent reply other threads:[~2019-01-10 18:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 19:47 [Cake] [PATCH 0/4] sched: Fix qdisc interactions exposed by using sch_cake as a leaf qdisc Toke Høiland-Jørgensen
2019-01-07 19:47 ` [Cake] [PATCH 1/4] sched: Avoid dereferencing skb pointer after child enqueue Toke Høiland-Jørgensen
2019-01-09 1:38 ` Cong Wang
2019-01-09 8:14 ` Toke Høiland-Jørgensen
2019-01-10 18:16 ` Cong Wang [this message]
2019-01-07 19:47 ` [Cake] [PATCH 2/4] sched: Fix detection of empty queues in child qdiscs Toke Høiland-Jørgensen
2019-01-07 19:57 ` Dave Taht
2019-01-07 19:47 ` [Cake] [PATCH 3/4] sch_api: Allow reducing queue backlog by a negative value Toke Høiland-Jørgensen
2019-01-07 20:54 ` Eric Dumazet
2019-01-08 9:55 ` Toke Høiland-Jørgensen
2019-01-07 19:47 ` [Cake] [PATCH 4/4] sch_cake: Correctly update parent qlen when splitting GSO packets Toke Høiland-Jørgensen
2019-01-08 21:30 ` [Cake] [PATCH 0/4] sched: Fix qdisc interactions exposed by using sch_cake as a leaf qdisc David Miller
2019-01-09 8:37 ` Toke Høiland-Jørgensen
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