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From: Qingfang Deng <qingfang.deng@linux.dev>
To: Linus Walleij <linusw@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	Simon Horman <horms@kernel.org>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	Jonas Gorski <jonas.gorski@gmail.com>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Woojung Huh <woojung.huh@microchip.com>,
	UNGLinuxDriver@microchip.com,
	"Chester A. Unal" <chester.a.unal@arinc9.com>,
	Daniel Golle <daniel@makrotopia.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
	Wei Fang <wei.fang@nxp.com>,
	Clark Wang <xiaoning.wang@nxp.com>,
	=?utf-8?b?Q2zDqW1lbnQgTMOpZ2Vy?= <clement.leger@bootlin.com>,
	George McCollister <george.mccollister@gmail.com>,
	David Yang <mmyangfl@gmail.com>,
	netdev@vger.kernel.org,
	Sashiko AI Review <sashiko-bot@kernel.org>
Subject: Re: [PATCH net-next v2] net: dsa: Fix skb ownership in taggers
Date: Wed, 17 Jun 2026 10:22:47 +0800
Message-ID: <20260617022248.1500-1-qingfang.deng@linux.dev>
In-Reply-To: <20260616-dsa-fix-free-skb-v2-1-9dbda6a19e97@kernel.org>
References: <20260616-dsa-fix-free-skb-v2-1-9dbda6a19e97@kernel.org>
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On 16 Jun 2026 at 11:36:22 +0200, Linus Walleij wrote:
> --- a/net/dsa/tag_rtl4_a.c
> +++ b/net/dsa/tag_rtl4_a.c
> @@ -41,8 +41,10 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
>  	u16 out;
>  
>  	/* Pad out to at least 60 bytes */
> -	if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false)))
> +	if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false))) {
> +		kfree_skb(skb);
>  		return NULL;
> +	}

This can be simplified to eth_skb_pad().

>  
>  	netdev_dbg(dev, "add realtek tag to package to port %d\n",
>  		   dp->index);
> --- a/net/dsa/tag_rzn1_a5psw.c
> +++ b/net/dsa/tag_rzn1_a5psw.c
> @@ -48,7 +48,7 @@ static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *de
>  	 * least 60 bytes otherwise they will be discarded when they enter the
>  	 * switch port logic.
>  	 */
> -	if (__skb_put_padto(skb, ETH_ZLEN, false))
> +	if (skb_put_padto(skb, ETH_ZLEN))
>  		return NULL;

Same here.

>  
>  	/* provide 'A5PSW_TAG_LEN' bytes additional space */

- Qingfang