Re: [PATCH iwl-net v2] igc: fix potential skb leak in igc_fpe_xmit_smd_frame()

["Abdul Rahim, Faizal" <faizal.abdul.rahim@linux.intel.com>]

On 15/4/2026 10:52 am, Kohei Enju wrote:
> When igc_fpe_init_tx_descriptor() fails, no one takes care of an
> allocated skb, leaking it. [1]
> Use dev_kfree_skb_any() on failure.
> 
> Tested on an I226 adapter with the following command, while injecting
> faults in igc_fpe_init_tx_descriptor() to trigger the error path.
>   # ethtool --set-mm $DEV verify-enabled on tx-enabled on pmac-enabled on
> 
> [1]
> unreferenced object 0xffff888113c6cdc0 (size 224):
> ...
>    backtrace (crc be3d3fda):
>      kmem_cache_alloc_node_noprof+0x3b1/0x410
>      __alloc_skb+0xde/0x830
>      igc_fpe_xmit_smd_frame.isra.0+0xad/0x1b0
>      igc_fpe_send_mpacket+0x37/0x90
>      ethtool_mmsv_verify_timer+0x15e/0x300
> 
> Cc: stable@vger.kernel.org
> Fixes: 5422570c0010 ("igc: add support for frame preemption verification")
> Signed-off-by: Kohei Enju <kohei@enjuk.jp>
> ---
> Changes:
>    v2:
>      - change to idiomatic style with goto (Simon)
>      - add Cc to stable (Alex)
>      - add reprodunction steps (Alex)
>    v1: https://lore.kernel.org/all/20260329145122.126040-1-kohei@enjuk.jp/
> ---
>   drivers/net/ethernet/intel/igc/igc_tsn.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
> index 8a110145bfee..02dd9f0290a3 100644
> --- a/drivers/net/ethernet/intel/igc/igc_tsn.c
> +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
> @@ -109,10 +109,16 @@ static int igc_fpe_xmit_smd_frame(struct igc_adapter *adapter,
>   	__netif_tx_lock(nq, cpu);
>   
>   	err = igc_fpe_init_tx_descriptor(ring, skb, type);
> -	igc_flush_tx_descriptors(ring);
> +	if (err)
> +		goto err_free_skb_any;
>   
> +	igc_flush_tx_descriptors(ring);
>   	__netif_tx_unlock(nq);
> +	return 0;
>   
> +err_free_skb_any:
> +	__netif_tx_unlock(nq);
> +	dev_kfree_skb_any(skb);
>   	return err;
>   }
>   

Thanks for helping to fix this.

Reviewed-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>