Re: [PATCH net] igc: return XSK frame copies on XDP_TX failure

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

On Fri, Oct 23, 2026 at 02:13:42PM +0000, Paul Moses wrote:
> Converting an XSK buffer to an XDP frame allocates a page and returns
> the original buffer to its pool. If the TX ring is full or DMA mapping
> fails, igc_xdp_xmit_back() returns an error without freeing the copy.
> The RX cleaner cannot release it, so the page leaks.
> 
> Return the copied frame on TX failure. Save the RX memory type before
> conversion so native frames remain RX-owned on failure.
> 
> Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
> Cc: stable@vger.kernel.org
> Signed-off-by: Paul Moses <p@1g4.org>
> ---
> Tested on Intel I225-V with baseline and patched kernels. Physical
> pause-frame backpressure caused 46 leaked copies on the baseline.
> With the fix, all 72 rejected copies were returned once and freed,
> and all 192 copies were accounted for. 
> 
>  drivers/net/ethernet/intel/igc/igc_main.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
> index 1fb5f3cbe93c..39263fd04aa9 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -2487,6 +2487,7 @@ struct igc_ring *igc_get_tx_ring(struct igc_adapter *adapter, int cpu)
>  
>  static int igc_xdp_xmit_back(struct igc_adapter *adapter, struct xdp_buff *xdp)
>  {
> +	enum xdp_mem_type mem_type = xdp->rxq->mem.type;

small nit is we require a concept called RCT (reverse christmas tree)
which makes you to order variable declarations from longest line to
shortest.

>  	struct xdp_frame *xdpf = xdp_convert_buff_to_frame(xdp);
>  	int cpu = smp_processor_id();
>  	struct netdev_queue *nq;
> @@ -2504,6 +2505,10 @@ static int igc_xdp_xmit_back(struct igc_adapter *adapter, struct xdp_buff *xdp)
>  	txq_trans_cond_update(nq);
>  	res = igc_xdp_init_tx_descriptor(ring, xdpf);
>  	__netif_tx_unlock(nq);
> +
> +	if (res && mem_type == MEM_TYPE_XSK_BUFF_POOL)
> +		xdp_return_frame(xdpf);

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

> +
>  	return res;
>  }
>  
> -- 
> 2.56.GIT
> 
> 
>