[Intel-wired-lan] [PATCH iwl-next v4] ixgbe: Fix possible skb NULL pointer dereference

[Tony Nguyen]

On 1/31/2025 4:14 AM, Piotr Kwapulinski wrote:
> The commit c824125cbb18 ("ixgbe: Fix passing 0 to ERR_PTR in
> ixgbe_run_xdp()") stopped utilizing the ERR-like macros for xdp status
> encoding. Propagate this logic to the ixgbe_put_rx_buffer().
> 
> The commit also relaxed the skb NULL pointer check - caught by Smatch.
> Restore this check.
> 
> Fixes: c824125cbb18 ("ixgbe: Fix passing 0 to ERR_PTR in ixgbe_run_xdp()")
> Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
> Acked-by: Maciej Fijalkowski <maciej.fijalkowski at intel.com>
> Signed-off-by: Piotr Kwapulinski <piotr.kwapulinski at intel.com>
> ---
> v1 -> v2
>    Provide extra details in commit message for motivation of this patch
> v2 -> v3
>    Simplify the check condition
> v3 -> v4
>    Rebase to net-queue

Applied to net-queue; the target tree should have been updated as well 
(iwl-net).

I'm also adding in the Closes: for the report.

Closes: 
https://lore.kernel.org/intel-wired-lan/2c7d6c31-192a-4047-bd90-9566d0e14cc0@stanley.mountain/

Thanks,
Tony

> ---
>   drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 7236f20..467f812 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -2105,7 +2105,7 @@ static void ixgbe_put_rx_buffer(struct ixgbe_ring *rx_ring,
>   		/* hand second half of page back to the ring */
>   		ixgbe_reuse_rx_page(rx_ring, rx_buffer);
>   	} else {
> -		if (!IS_ERR(skb) && IXGBE_CB(skb)->dma == rx_buffer->dma) {
> +		if (skb && IXGBE_CB(skb)->dma == rx_buffer->dma) {
>   			/* the page has been released from the ring */
>   			IXGBE_CB(skb)->page_released = true;
>   		} else {