netdev - Re: [PATCH bpf] bpf: Fix metadata_dst leak __bpf_redirect_neigh

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Message-ID: <1587bfe1-8672-4677-b76e-ab516e5c52c5@iogearbox.net>
Date: Fri, 3 Oct 2025 21:24:00 +0200
From: Daniel Borkmann <daniel@...earbox.net>
To: Jakub Kicinski <kuba@...nel.org>
Cc: bpf@...r.kernel.org, netdev@...r.kernel.org,
 Yusuke Suzuki <yusuke.suzuki@...valent.com>,
 Julian Wiedmann <jwi@...valent.com>, Martin KaFai Lau
 <martin.lau@...nel.org>, Jordan Rife <jrife@...gle.com>
Subject: Re: [PATCH bpf] bpf: Fix metadata_dst leak
 __bpf_redirect_neigh_v{4,6}

On 10/3/25 6:02 PM, Jakub Kicinski wrote:
> On Fri,  3 Oct 2025 09:34:18 +0200 Daniel Borkmann wrote:
>> Cilium has a BPF egress gateway feature which forces outgoing K8s Pod
>> traffic to pass through dedicated egress gateways which then SNAT the
>> traffic in order to interact with stable IPs outside the cluster.
> 
> Nice! The warning Stan added at work?

We should add CONFIG_DEBUG_NET to our Cilium CI test kernels actually.
The memory leak was observed on AWS nodes with the above Cilium config,
so bpftrace came to the rescue in the end.

Thanks,
Daniel