Re: [PATCH V2 RFC 2/2] ARM: dts: BCM5301X: change Luxul XWR-3150 CPU port from 5 do 8

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The patch assigns the exact same MAC address nvmem cell to both `gmac0` and `gmac2`, while leaving `gmac0` enabled, causing a ghost interface and MAC address collision.
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--- Patch [2]: [PATCH V2 RFC 2/2] ARM: dts: BCM5301X: change Luxul XWR-3150 CPU port from 5 do 8 ---
commit 0c244661a37f1cbd846bc54d786e2d6320794031
Author: Rafał Miłecki <rafal@milecki.pl>
ARM: dts: BCM5301X: change Luxul XWR-3150 CPU port from 5 do 8

This commit changes the CPU port for the Luxul XWR-3150 from port 5 to port 8
to utilize full switch functionality. It assigns the MAC address originally
intended for the first Ethernet interface to the third Ethernet interface and
updates the switch port statuses accordingly.

> diff --git a/arch/arm/boot/dts/broadcom/bcm47094-luxul-xwr-3150-v1.dts b/arch/arm/boot/dts/broadcom/bcm47094-luxul-xwr-3150-v1.dts
> index 8e487f60a2cca..7969f0f331b56 100644
> --- a/arch/arm/boot/dts/broadcom/bcm47094-luxul-xwr-3150-v1.dts
> +++ b/arch/arm/boot/dts/broadcom/bcm47094-luxul-xwr-3150-v1.dts
> @@ -81,6 +81,11 @@ &gmac0 {
>  	nvmem-cell-names = "mac-address";
>  };
>  
> +&gmac2 {
> +	nvmem-cells = <&et0macaddr 0>;
> +	nvmem-cell-names = "mac-address";
> +};
> +

[Severity: High]
Since gmac0 is not marked as disabled and uses the exact same MAC address cell
(&et0macaddr 0), won't the bgmac Ethernet driver probe both gmac0 and gmac2
and register two distinct network interfaces with the same MAC address?

Because gmac0 retains its fixed-link property but switch port 5 is now
disabled, does this leave a ghost interface that is reported as UP but
disconnected from the switch, potentially blackholing traffic?

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260811193658.14304-1-zajec5@gmail.com?part=2