Re: [PATCH net] net: ethernet: ti: am65-cpsw-nuss: Fix skb size by accounting for skb_shared_info

[Siddharth Vadapalli <s-vadapalli@ti.com>]

On Wed, Jun 25, 2025 at 04:57:25PM +0530, Chintan Vankar wrote:

Hello Chintan,

> While transitioning from netdev_alloc_ip_align to build_skb, memory for

nitpick: Add parantheses when referring to functions:
netdev_alloc_ip_align()
build_skb()

> skb_shared_info was not allocated. Fix this by including

Enclose structures within double quotes and preferably refer to them
in the context of an "skb":

...memory for the "skb_shared_info" member of an "skb" was not allocated...

> sizeof(skb_shared_info) in the packet length during allocation.
> 
> Fixes: 8acacc40f733 ("net: ethernet: ti: am65-cpsw: Add minimal XDP support")

> Signed-off-by: Chintan Vankar <c-vankar@ti.com>
> ---
> 
> This patch is based on the commit '9caca6ac0e26' of origin/main branch of
> Linux-net repository.
> 
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index f20d1ff192ef..3905eec0b11e 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -857,6 +857,7 @@ static struct sk_buff *am65_cpsw_build_skb(void *page_addr,
>  	struct sk_buff *skb;
>  
>  	len += AM65_CPSW_HEADROOM;
> +	len += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

This could be added to the previous line itself:

	len += AM65_CPSW_HEADROOM + SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

>  
>  	skb = build_skb(page_addr, len);
>  	if (unlikely(!skb))

Thank you for finding the bug and fixing it.

Regards,
Siddharth.