Re: [PATCH iwl-next v3] ixgbe: Fix possible skb NULL pointer dereference

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Mon, Jan 27, 2025 at 11:38:36AM +0100, 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@linaro.org>
> Signed-off-by: Piotr Kwapulinski <piotr.kwapulinski@intel.com>
> ---
>  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 {
> -- 
> v1 -> v2
>   Provide extra details in commit message for motivation of this patch.
> v2 -> v3
>   Simplify the check condition

Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

Thanks!

> 
> 2.43.0
>