Re: [PATCH net v2 1/1] net: l2tp: do not propagate multicast notification errors

[Simon Horman <horms@kernel.org>]

On Thu, Aug 20, 2026 at 06:40:28PM +0000, Zihan Xi wrote:
> The tunnel create, tunnel modify, session create, and session modify
> netlink handlers send multicast notifications through helpers that can fail
> while allocating or encoding a message, or while multicasting it.
> 
> For tunnel and session create/modify, a notification is sent after the live
> operation has completed. Returning a best-effort notification error as the
> command result can therefore report failure for an operation that already
> committed and can cause callers to retry and accumulate live objects.
> 
> Keep sending notifications for listener visibility, but do not propagate
> their best-effort status as the command result. This also keeps the tunnel
> modify command consistent with the other notification-only paths.
> 
> 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>
> ---
> changes in v2:
>   - Extend best-effort notification handling to tunnel_modify.
>   - Follow the existing bare-call style instead of explicit (void) casts.
>   - Document the observed ENOBUFS and committed-state reproduction.
>   - v1 Link: https://lore.kernel.org/all/cover.1786962220.git.zihanx@nebusec.ai/

Thanks for the updates.

Reviewed-by: Simon Horman <horms@kernel.org>