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Miller" , David Ahern , Eric Dumazet , Paolo Abeni , Simon Horman , Martin KaFai Lau , netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@cloudflare.com Subject: Re: [PATCH net v2] net: Clear skb metadata in LWT BPF xmit In-Reply-To: <20260518161827.2ac4766f@kernel.org> (Jakub Kicinski's message of "Mon, 18 May 2026 16:18:27 -0700") References: <20260514-bpf-lwt-drop-skb-metadata-v2-1-458664edc2b5@cloudflare.com> <20260518161827.2ac4766f@kernel.org> Date: Tue, 19 May 2026 11:47:49 +0200 Message-ID: <87h5o3ohmi.fsf@cloudflare.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, May 18, 2026 at 04:18 PM -07, Jakub Kicinski wrote: > On Thu, 14 May 2026 12:47:09 +0200 Jakub Sitnicki wrote: >> + /* LWT BPF programs cannot access skb metadata but can corrupt >> + * it with helpers that operate on skb headroom. Drop it. >> + */ >> + skb_metadata_clear(skb); > > Sashiko has a point, right? Is there something in LWT which would > prevent us from working on clones? Totally. I've just been spread a little thin lately. We have a bpf/selftest that uses tc act mirred that exercises this scenario that I need to extend. In general, anything high/med from LLMs won't go unaddressed.