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

[Simon Horman <horms@kernel.org>]

On Fri, May 23, 2025 at 09:58:57AM +0800, Jianbo Liu wrote:
> 
> 
> 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, much appreciated.