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 <20220512123313.218063-3-imagedong@tencent.com> <20220512091558.350899ff@kernel.org>
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From:   Eric Dumazet <edumazet@google.com>
Date:   Thu, 12 May 2022 09:16:38 -0700
Message-ID: <CANn89iLEkgat-es15Sb2naWn8VProMK1_wr7jBe4L4bXs4JVWA@mail.gmail.com>
Subject: Re: [PATCH net-next v2 2/4] net: skb: check the boundrary of drop
 reason in kfree_skb_reason()
To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Menglong Dong <menglong8.dong@gmail.com>,
        Neil Horman <nhorman@tuxdriver.com>,
        David Miller <davem@davemloft.net>,
        Paolo Abeni <pabeni@redhat.com>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Menglong Dong <imagedong@tencent.com>,
        Martin KaFai Lau <kafai@fb.com>,
        Talal Ahmad <talalahmad@google.com>,
        Kees Cook <keescook@chromium.org>,
        Pavel Begunkov <asml.silence@gmail.com>,
        Willem de Bruijn <willemb@google.com>,
        Vasily Averin <vasily.averin@linux.dev>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        Luiz Augusto von Dentz <luiz.von.dentz@intel.com>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>
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On Thu, May 12, 2022 at 9:16 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 12 May 2022 20:33:11 +0800 menglong8.dong@gmail.com wrote:
> > +     if (unlikely(reason <= 0 || reason >= SKB_DROP_REASON_MAX)) {
> > +             DEBUG_NET_WARN_ON_ONCE(1);
> > +             reason = SKB_DROP_REASON_NOT_SPECIFIED;
> > +     }
>
> With drop_monitor fixes sending an invalid reason to the tracepoint
> should be a minor bug, right?
>
> Can we just have a:
>
>         DEBUG_NET_WARN_ON_ONCE(reason <= 0 || reason >= SKB_DROP_REASON_MAX);
>
> and avoid having this branch on non-debug builds?

Exactly what I was going to say.