In mlx5_chains_create_table(), the return value of mlx5_get_fdb_sub_ns()
and mlx5_get_flow_namespace() must be checked to prevent NULL pointer
dereferences. If either function fails, the function should log error
message with mlx5_core_warn() and return error pointer.

Fixes: 39ac237ce009 ("net/mlx5: E-Switch, Refactor chains and priorities")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
[v1]->[v2]: Add Fixes tag and branch target. Change return value.
[v2]->[v3]: Change Fixes tag. Move change history.
---
 drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
index a80ecb672f33..711d14dea248 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
@@ -196,6 +196,11 @@ mlx5_chains_create_table(struct mlx5_fs_chains *chains,
 		ns = mlx5_get_flow_namespace(chains->dev, chains->ns);
 	}
 
+	if (!ns) {
+		mlx5_core_warn(chains->dev, "Failed to get flow namespace\n");
+		return ERR_PTR(-EOPNOTSUPP);
+	}
+
 	ft_attr.autogroup.num_reserved_entries = 2;
 	ft_attr.autogroup.max_num_groups = chains->group_num;
 	ft = mlx5_create_auto_grouped_flow_table(ns, &ft_attr);
-- 
2.42.0.windows.2

On 07/03/2025 4:18, Wentao Liang wrote:
> In mlx5_chains_create_table(), the return value of mlx5_get_fdb_sub_ns()
> and mlx5_get_flow_namespace() must be checked to prevent NULL pointer
> dereferences. If either function fails, the function should log error
> message with mlx5_core_warn() and return error pointer.
> 
> Fixes: 39ac237ce009 ("net/mlx5: E-Switch, Refactor chains and priorities")
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
> ---
> [v1]->[v2]: Add Fixes tag and branch target. Change return value.
> [v2]->[v3]: Change Fixes tag. Move change history.
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
> index a80ecb672f33..711d14dea248 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/fs_chains.c
> @@ -196,6 +196,11 @@ mlx5_chains_create_table(struct mlx5_fs_chains *chains,
>   		ns = mlx5_get_flow_namespace(chains->dev, chains->ns);
>   	}
>   
> +	if (!ns) {
> +		mlx5_core_warn(chains->dev, "Failed to get flow namespace\n");
> +		return ERR_PTR(-EOPNOTSUPP);
> +	}
> +
>   	ft_attr.autogroup.num_reserved_entries = 2;
>   	ft_attr.autogroup.max_num_groups = chains->group_num;
>   	ft = mlx5_create_auto_grouped_flow_table(ns, &ft_attr);

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

Thanks.

I suggest to reconsider the patch version number selection once more.


> In mlx5_chains_create_table(), the return value of mlx5_get_fdb_sub_ns()
> and mlx5_get_flow_namespace() must be checked to prevent NULL pointer
> dereferences. If either function fails, the function should log error
> message with mlx5_core_warn() and return error pointer.

Please improve such a change description another bit.

See also:
https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14-rc5#n94

Regards,
Markus