Re: [net-next PATCH v13 2/9] net: dsa: realtek: rtl8365mb: reject unsupported topologies

[Mieczyslaw Nalewaj]

On 6/6/2026 10:29 AM, Luiz Angelo Daros de Luca wrote:
> Explicitly enforce the presence of a CPU port (-EINVAL) and reject DSA
> cascade links (-EOPNOTSUPP) during setup to prevent silent failures.
> 
> These topologies were already non-functional. Without a CPU port, the
> driver does not activate CPU tagging. Additionally, the switch hardware
> was not designed to be cascaded, and DSA links never worked because
> CPU tagging is not enabled for them.
> 
> Reviewed-by: Mieczyslaw Nalewaj <namiltd@xxxxxxxxx>
> Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> Signed-off-by: Luiz Angelo Daros de Luca <luizluca@xxxxxxxxx>
> ---
[...]
>drivers/net/dsa/realtek/rtl8365mb.c:rtl8365mb_get_stats64() {
>    ...
>	mb = priv->chip_data;
>	p = &mb->ports[port];
>	spin_lock(&p->stats_lock);
>	memcpy(s, &p->stats, sizeof(*s));
>	spin_unlock(&p->stats_lock);
>}

Sashiko reports a potential deadlock around stats_lock, however I couldn't find a call chain reaching rtl8365mb_get_stats64() from softirq context. Can anyone point to such a path?