Re: [PATCH net] udp: resubmit encap packets for secondary mcast sockets

On Fri, Sep 18, 2026 at 10:00 AM Mariano Baragiola [off-list ref] wrote:

On Fri, Sep 18, 2026 at 9:21 AM Kuniyuki Iwashima [off-list ref] wrote:

quoted

Did you see a real problem or is this triggered by an AI report?

https://lore.kernel.org/netdev/20260415203624.4057135-1-kuniyu@google.com/ (local)

Hi Kuniyuki,

To be completely transparent: this was identified during a code audit following
commit 3cb8d4b9bfeb, not from a production crash report.

I recognize that standard FOU configurations do not typically have multiple listeners
on the same port (returning -EADDRINUSE), so this primarily affects
multi-socket/SO_REUSEPORT encapsulation scenarios. If you consider this an
edge case not worth touching, I am completely fine dropping the patch.

Since the patch adds ip_protocol_deliver_rcu(), syzbot will find a
way to trigger stack overflow, so I think it's not worth a fix unless
there is a real use case.