Re: [PATCH net] net/mlx5e: psp, avoid 'accel' NULL pointer dereference

Michal Swiatkowski
2025-10-15T07:36:59Z

On Wed, Oct 15, 2025 at 10:05:23AM +0300, Tariq Toukan wrote:
> From: Cosmin Ratiu <cratiu@nvidia.com>
>
> The 'accel' parameter of mlx5e_txwqe_build_eseg_csum() and the similar
> 'state' parameter of mlx5e_accel_tx_ids_len() were NULL when called
> from mlx5i_sq_xmit() and were causing kernel panics from that context.
>
> Fix that by passing in a local empty mlx5e_accel_tx_state variable, thus
> guaranteeing that 'accel' is never NULL. Also remove an unnecessary
> check from mlx5e_tx_wqe_inline_mode().
>
> Fixes: e5a1861a298e ("net/mlx5e: Implement PSP Tx data path")
> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
> index b7227afcb51d..2702b3885f06 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
> @@ -256,7 +256,7 @@ mlx5e_tx_wqe_inline_mode(struct mlx5e_txqsq *sq, struct sk_buff *skb,
> u8 mode;
>
> #ifdef CONFIG_MLX5_EN_TLS
> - if (accel && accel->tls.tls_tisn)
> + if (accel->tls.tls_tisn)
> return MLX5_INLINE_MODE_TCP_UDP;
> #endif
>
> @@ -982,6 +982,7 @@ void mlx5i_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,
> struct mlx5e_tx_attr attr;
> struct mlx5i_tx_wqe *wqe;
>
> + struct mlx5e_accel_tx_state accel = {};
> struct mlx5_wqe_datagram_seg *datagram;
> struct mlx5_wqe_ctrl_seg *cseg;
> struct mlx5_wqe_eth_seg *eseg;
> @@ -992,7 +993,7 @@ void mlx5i_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,
> int num_dma;
> u16 pi;
>
> - mlx5e_sq_xmit_prepare(sq, skb, NULL, &attr);
> + mlx5e_sq_xmit_prepare(sq, skb, &accel, &attr);
> mlx5i_sq_calc_wqe_attr(skb, &attr, &wqe_attr);
>
> pi = mlx5e_txqsq_get_next_pi(sq, wqe_attr.num_wqebbs);
> @@ -1009,7 +1010,7 @@ void mlx5i_sq_xmit(struct mlx5e_txqsq *sq, struct sk_buff *skb,
>
> mlx5i_txwqe_build_datagram(av, dqpn, dqkey, datagram);
>
> - mlx5e_txwqe_build_eseg_csum(sq, skb, NULL, eseg);
> + mlx5e_txwqe_build_eseg_csum(sq, skb, &accel, eseg);
>
> eseg->mss = attr.mss;

Looks good
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>

>
>
> base-commit: 7f0fddd817ba6daebea1445ae9fab4b6d2294fa8
> --
> 2.31.1