Subject: Re: [PATCH net 1/2] mlx5: fix possible ptp queue fifo overflow

From: Leon Romanovsky <[email-masked]>
Date: Mon, 23 Jan 2023 09:20:28 +0200

On Sun, Jan 22, 2023 at 08:16:01AM -0800, Vadim Fedorenko wrote:
> Fifo pointers are not checked for overflow and this could potentially
> lead to overflow and double free under heavy PTP traffic.
> 
> Also there were accidental OOO cqe which lead to absolutely broken fifo.
> Add checks to workaround OOO cqe and add counters to show the amount of
> such events.
> 
> Fixes: 19b43a432e3e ("net/mlx5e: Extend SKB room check to include PTP-SQ")
> Signed-off-by: Vadim Fedorenko <[email-masked]>
> ---
>  .../net/ethernet/mellanox/mlx5/core/en/ptp.c  | 28 ++++++++++++++-----
>  .../net/ethernet/mellanox/mlx5/core/en/txrx.h |  6 +++-
>  .../ethernet/mellanox/mlx5/core/en_stats.c    |  2 ++
>  .../ethernet/mellanox/mlx5/core/en_stats.h    |  2 ++
>  4 files changed, 30 insertions(+), 8 deletions(-)

<...>

> @@ -291,12 +291,16 @@ void mlx5e_skb_fifo_push(struct mlx5e_skb_fifo *fifo, struct sk_buff *skb)
>  {
>  	struct sk_buff **skb_item = mlx5e_skb_fifo_get(fifo, (*fifo->pc)++);
>  
> +	WARN_ONCE((u16)(*fifo->pc - *fifo->cc) > fifo->mask, "%s overflow", __func__);

nit, ""%s overflow", __func__" is not needed as call trace already includes function name.

Thanks