Re: [PATCH v3 net] net/mlx5: DR, prevent potential error pointer dereference

[Tariq Toukan]

On 04/12/2024 14:06, Dan Carpenter wrote:
> The dr_domain_add_vport_cap() function generally returns NULL on error
> but sometimes we want it to return ERR_PTR(-EBUSY) so the caller can
> retry.  The problem here is that "ret" can be either -EBUSY or -ENOMEM
> and if it's and -ENOMEM then the error pointer is propogated back and
> eventually dereferenced in dr_ste_v0_build_src_gvmi_qpn_tag().
>
> Fixes: 11a45def2e19 ("net/mlx5: DR, Add support for SF vports")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> v2: fix typo in commit message
> v3: better style
>
>   .../net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c  | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> index 3d74109f8230..49f22cad92bf 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_domain.c
> @@ -297,7 +297,9 @@ dr_domain_add_vport_cap(struct mlx5dr_domain *dmn, u16 vport)
>   	if (ret) {
>   		mlx5dr_dbg(dmn, "Couldn't insert new vport into xarray (%d)\n", ret);
>   		kvfree(vport_caps);
> -		return ERR_PTR(ret);
> +		if (ret == -EBUSY)
> +			return ERR_PTR(-EBUSY);
> +		return NULL;
>   	}
>   
>   	return vport_caps;

Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>

Thanks.