Re: [PATCH net 2/2] net/mlx5e: Fix leak of Geneve TLV option object

[Jianbo Liu <jianbol@nvidia.com>]

On 5/23/2025 3:16 AM, Simon Horman wrote:
> On Thu, May 22, 2025 at 09:28:06AM +0300, Tariq Toukan wrote:
>> From: Jianbo Liu <jianbol@nvidia.com>
>>
>> Previously, a unique tunnel id was added for the matching on TC
>> non-zero chains, to support inner header rewrite with goto action.
>> Later, it was used to support VF tunnel offload for vxlan, then for
>> Geneve and GRE. To support VF tunnel, a temporary mlx5_flow_spec is
>> used to parse tunnel options. For Geneve, if there is TLV option, a
>> object is created, or refcnt is added if already exists. But the
>> temporary mlx5_flow_spec is directly freed after parsing, which causes
>> the leak because no information regarding the object is saved in
>> flow's mlx5_flow_spec, which is used to free the object when deleting
>> the flow.
>>
>> To fix the leak, call mlx5_geneve_tlv_option_del() before free the
>> temporary spec if it has TLV object.
>>
>> Fixes: 521933cdc4aa ("net/mlx5e: Support Geneve and GRE with VF tunnel offload")
>> Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
>> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
>> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
>> ---
>>   drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> index f1d908f61134..b9c1d7f8f05c 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
>> @@ -2028,9 +2028,8 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
>>   	return err;
>>   }
>>   
>> -static bool mlx5_flow_has_geneve_opt(struct mlx5e_tc_flow *flow)
>> +static bool mlx5_flow_has_geneve_opt(struct mlx5_flow_spec *spec)
>>   {
>> -	struct mlx5_flow_spec *spec = &flow->attr->parse_attr->spec;
>>   	void *headers_v = MLX5_ADDR_OF(fte_match_param,
>>   				       spec->match_value,
>>   				       misc_parameters_3);
>> @@ -2069,7 +2068,7 @@ static void mlx5e_tc_del_fdb_flow(struct mlx5e_priv *priv,
>>   	}
>>   	complete_all(&flow->del_hw_done);
>>   
>> -	if (mlx5_flow_has_geneve_opt(flow))
>> +	if (mlx5_flow_has_geneve_opt(&attr->parse_attr->spec))
>>   		mlx5_geneve_tlv_option_del(priv->mdev->geneve);
>>   
>>   	if (flow->decap_route)
> 
> Hi,
> 
> The lines leading up to the hung below are:
> 
> 	      err = mlx5e_tc_tun_parse(filter_dev, priv, tmp_spec, f, match_level);
>                if (err) {
>                          kvfree(tmp_spec);
>                          NL_SET_ERR_MSG_MOD(extack, "Failed to parse tunnel attributes");
>                          netdev_warn(priv->netdev, "Failed to parse tunnel attributes");
> 
> I am wondering if the same resource leak described in the patch description
> can occur if mlx5e_tc_tun_parse() fails after it successfully calls
> tunnel->parse_tunnel().
> 

Yes, I missed that. I will fix in next version.

Thanks!
Jianbo

>> @@ -2580,6 +2579,8 @@ static int parse_tunnel_attr(struct mlx5e_priv *priv,
>>   			return err;
>>   		}
>>   		err = mlx5e_tc_set_attr_rx_tun(flow, tmp_spec);
>> +		if (mlx5_flow_has_geneve_opt(tmp_spec))
>> +			mlx5_geneve_tlv_option_del(priv->mdev->geneve);
>>   		kvfree(tmp_spec);
>>   		if (err)
>>   			return err;
>> -- 
>> 2.31.1
>>
>>