[PATCH] ice: fix pktgen crash in eswitch mode

[PATCH] ice: fix pktgen crash in eswitch mode

[Lorenz Brun]

When pktgen reuses an skb on an ICE port representor, the representor
forwards it to the uplink through dev_queue_xmit(). If the lower qdisc
retains the skb, a subsequent transmission of the same skb overwrites
its list pointers. Dequeuing it from qdisc->gso_skb then dereferences a
NULL skb->next in __skb_unlink().

Disable SKB reuse for this ice path to prevent this.

Crash signature:
   __dev_queue_xmit+0x5c9/0xf20
   ice_eswitch_port_start_xmit+0x83/0xd0 [ice]
   pktgen_thread_worker+0x82f/0x1c10 [pktgen]

Signed-off-by: Lorenz Brun <lorenz@monogon.tech>
---
 drivers/net/ethernet/intel/ice/ice_repr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_repr.c b/drivers/net/ethernet/intel/ice/ice_repr.c
index 096566c697f4..2603cb0f6a54 100644
--- a/drivers/net/ethernet/intel/ice/ice_repr.c
+++ b/drivers/net/ethernet/intel/ice/ice_repr.c
@@ -305,6 +305,7 @@ ice_repr_reg_netdev(struct net_device *netdev, const struct net_device_ops *ops)
 	eth_hw_addr_random(netdev);
 	netdev->netdev_ops = ops;
 	ice_set_ethtool_repr_ops(netdev);
+	netdev->priv_flags &= ~IFF_TX_SKB_SHARING;
 
 	netdev->hw_features |= NETIF_F_HW_TC;
 
-- 
2.54.0

RE: [PATCH] ice: fix pktgen crash in eswitch mode

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Lorenz Brun <lorenz@monogon.tech>
> Sent: Saturday, September 26, 2026 12:27 AM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
> <andrew+netdev@lunn.ch>; David S. Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>
> Cc: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [PATCH] ice: fix pktgen crash in eswitch mode
> 
> When pktgen reuses an skb on an ICE port representor, the representor
> forwards it to the uplink through dev_queue_xmit(). If the lower qdisc
> retains the skb, a subsequent transmission of the same skb overwrites
> its list pointers. Dequeuing it from qdisc->gso_skb then dereferences
> a NULL skb->next in __skb_unlink().
> 
> Disable SKB reuse for this ice path to prevent this.
> 
> Crash signature:
>    __dev_queue_xmit+0x5c9/0xf20
>    ice_eswitch_port_start_xmit+0x83/0xd0 [ice]
>    pktgen_thread_worker+0x82f/0x1c10 [pktgen]
> 
I think this patch required fixes tag.
And if it's serios bugfix it needs to go [PATCH net]

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>


> Signed-off-by: Lorenz Brun <lorenz@monogon.tech>
> ---
>  drivers/net/ethernet/intel/ice/ice_repr.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_repr.c
> b/drivers/net/ethernet/intel/ice/ice_repr.c
> index 096566c697f4..2603cb0f6a54 100644
> --- a/drivers/net/ethernet/intel/ice/ice_repr.c
> +++ b/drivers/net/ethernet/intel/ice/ice_repr.c
> @@ -305,6 +305,7 @@ ice_repr_reg_netdev(struct net_device *netdev,
> const struct net_device_ops *ops)
>  	eth_hw_addr_random(netdev);
>  	netdev->netdev_ops = ops;
>  	ice_set_ethtool_repr_ops(netdev);
> +	netdev->priv_flags &= ~IFF_TX_SKB_SHARING;
> 
>  	netdev->hw_features |= NETIF_F_HW_TC;
> 
> --
> 2.54.0