Subject: Re: [PATCH v2 1/3] net: lan966x: fix page_pool error handling in lan966x_fdma_rx_alloc_page_pool()

From: Jakub Kicinski <[email-masked]>
Date: Fri, 3 Apr 2026 16:17:20 -0700

On Sat,  4 Apr 2026 00:07:12 +0100 David Carlier wrote:
> page_pool_create() can return an ERR_PTR on failure. The return value
> is used unconditionally in the loop that follows, passing the error
> pointer through xdp_rxq_info_reg_mem_model() into page_pool_use_xdp_mem(),
> which dereferences it, causing a kernel oops.
> 
> Add an IS_ERR check after page_pool_create() to return early on failure.

Wow, that was fast, are you generating this patches with AI?
You've written and tested this code in 40min?

Please with at least 24h before sending v3, per:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html

You're missing a cover letter, if there's more than 2 patches the
series must have a cover letter.

> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> index 7b6369e43451..34bbcae2f068 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
> @@ -92,6 +92,9 @@ static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
>  
>  	rx->page_pool = page_pool_create(&pp_params);
>  

no empty lines between call and its error check, fix this in all
checks you're adding

> +	if (unlikely(IS_ERR(rx->page_pool)))
> +		return PTR_ERR(rx->page_pool);
> +
>  	for (int i = 0; i < lan966x->num_phys_ports; ++i) {
>  		struct lan966x_port *port;
>