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Date:   Mon, 31 Jul 2023 16:52:37 -0700
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Subject: Re: [PATCH v4 bpf 1/2] bpf: fix skb_do_redirect return values
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To:     Yan Zhai <yan@cloudflare.com>
Cc:     bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-kselftest@vger.kernel.org, kernel-team@cloudflare.com,
        Jordan Griege <jgriege@cloudflare.com>,
        Markus Elfring <Markus.Elfring@web.de>,
        Jakub Sitnicki <jakub@cloudflare.com>
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 <266ab56e-ae83-7ddc-618e-3af228df81bd@linux.dev>
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 <2f285967-6cc0-c492-6a79-edc233c1368e@linux.dev>
 <CAO3-PboZ5eQUbL3UO1HsaQ0s5CyS0ch=ksFVP1R6s8zv0+FTAg@mail.gmail.com>
From:   Martin KaFai Lau <martin.lau@linux.dev>
In-Reply-To: <CAO3-PboZ5eQUbL3UO1HsaQ0s5CyS0ch=ksFVP1R6s8zv0+FTAg@mail.gmail.com>
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On 7/31/23 4:01 PM, Yan Zhai wrote:
> What I commented was an exact same issue at different location: BPF
> reroute may trigger the crash as well, since it also returns
> dev_queue_xmit status in bpf_xmit. Need to fix this, or instead fixing
> LWTUNNEL_XMIT_CONTINUE value and correct the behavior at lwtunnel_xmit
> rather than bpf_xmit.

Ah. I think I got it. You meant the bpf_lwt_xmit_reroute() / BPF_LWT_REROUTE 
case? It would be clearer if some of these names were quoted instead. "reroute" 
could mean many things.

Please put details comment in v5. Thanks.

> 
> Yan
> 
>>
>>> As Dan suggested, packets might not have been freed when this is
>>> returned from drivers. The caller of dev_queue_xmit might need to free
>>> skb when this happens.
>>>
>>> Yan
>>