Re: [PATCH net 1/1] net: l2tp: ignore multicast notification errors in netlink commands

[Simon Horman <horms@kernel.org>]

On Mon, Aug 17, 2026 at 05:21:09PM +0000, Zihan Xi wrote:
> l2tp_nl_cmd_tunnel_create(), l2tp_nl_cmd_session_create(), and
> l2tp_nl_cmd_session_modify() update live state before sending their
> multicast notifications. A notification helper can fail while allocating
> or encoding the message, or while multicasting it. Returning any such
> best-effort notification error after the state change makes a successful
> command look like a failure and can cause retries to accumulate live
> objects.

Is this a theoretical problem, or something that has been observed?

> Keep sending notifications for listener visibility, but do not let their
> best-effort status overwrite the command result. The explicit (void) casts
> make this intentional for all notification helper failures.

I don't think the (void) cast is in keeping with the existing code
in this file.

> Fixes: 33f72e6f0c67 ("l2tp : multicast notification to the registered listeners")
> Cc: stable@vger.kernel.org
> Reported-by: Vega <vega@nebusec.ai>
> Assisted-by: Codex:gpt-5.4
> Signed-off-by: Zihan Xi <zihanx@nebusec.ai>

I am wondering if you considered extending this patch to
also cover l2tp_nl_cmd_tunnel_modify().

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