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From:   Eric Dumazet <edumazet@google.com>
Date:   Fri, 15 Sep 2023 14:57:35 +0200
Message-ID: <CANn89i+hM_eHSPUNwPCQZdtkk7O31GhaQ4AmhfBuZ=wQ3psb7w@mail.gmail.com>
Subject: Re: [PATCH] net: sched: hfsc: dont intepret cls results when asked to drop
To:     Ma Ke <make_ruc2021@163.com>
Cc:     jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
        davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On Fri, Sep 15, 2023 at 2:37=E2=80=AFPM Ma Ke <make_ruc2021@163.com> wrote:
>
> If asked to drop a packet via TC_ACT_SHOT it is unsafe to assume
> res.class contains a valid pointer.
>
> Signed-off-by: Ma Ke <make_ruc2021@163.com>
> ---
>  net/sched/sch_hfsc.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
> index 3554085bc2be..2a76027b14e6 100644
> --- a/net/sched/sch_hfsc.c
> +++ b/net/sched/sch_hfsc.c
> @@ -1135,6 +1135,8 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sc=
h, int *qerr)
>         head =3D &q->root;
>         tcf =3D rcu_dereference_bh(q->root.filter_list);
>         while (tcf && (result =3D tcf_classify(skb, NULL, tcf, &res, fals=
e)) >=3D 0) {
> +               if (result =3D=3D TC_ACT_SHOT)
> +                       return NULL;
>  #ifdef CONFIG_NET_CLS_ACT
>                 switch (result) {
>                 case TC_ACT_QUEUED:
> --
> 2.37.2
>

Same comment, already handled at iine 1145