Re: [PATCH] net/mlx5: fix potential null dereference when enable shared FDB

[Tariq Toukan <ttoukan.linux@gmail.com>]

On 03/04/2025 17:03, Tariq Toukan wrote:
> 
> 
> On 03/04/2025 12:52, Charles Han(韩春超) wrote:
>> -ENXIO indicates "No such device or address". I've found that in mlx5/ 
>> core, if mlx5_get_flow_namespace() returns null, it basically returns 
>> -EOPNOTSUPP.
>>
> 
> Please do not top-post.
> 
> +1.
> If namespace is not found it's due to lack of support.
> 
> 
>> -----邮件原件-----
>> 发件人: Przemek Kitszel <przemyslaw.kitszel@intel.com>
>> 发送时间: 2025年4月2日 19:02
>> 收件人: Charles Han(韩春超) <hanchunchao@inspur.com>
>> 抄送: netdev@vger.kernel.org; linux-rdma@vger.kernel.org; linux- 
>> kernel@vger.kernel.org; saeedm@nvidia.com; leon@kernel.org; 
>> tariqt@nvidia.com; andrew+netdev@lunn.ch; davem@davemloft.net; 
>> edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; 
>> markzhang@nvidia.com; mbloch@nvidia.com
>> 主题: Re: [PATCH] net/mlx5: fix potential null dereference when enable 
>> shared FDB
>>
>> On 4/2/25 11:43, Charles Han wrote:
>>> mlx5_get_flow_namespace() may return a NULL pointer, dereferencing it
>>> without NULL check may lead to NULL dereference.
>>> Add a NULL check for ns.
>>>
>>> Fixes: db202995f503 ("net/mlx5: E-Switch, add logic to enable shared
>>> FDB")
>>> Signed-off-by: Charles Han <hanchunchao@inspur.com>
> 
> Acked-by: Tariq Toukan <tariqt@nvidia.com>
> 

Re-visiting this...
See comment below.

>>> ---
>>>    .../net/ethernet/mellanox/mlx5/core/eswitch_offloads.c | 10 ++++++ 
>>> ++++
>>>    drivers/net/ethernet/mellanox/mlx5/core/fs_cmd.c       |  5 +++++
>>>    2 files changed, 15 insertions(+)
>>>
>>> diff --git
>>> a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
>>> b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
>>> index a6a8eea5980c..dc58e4c2d786 100644
>>> --- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
>>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
>>> @@ -2667,6 +2667,11 @@ static int esw_set_slave_root_fdb(struct 
>>> mlx5_core_dev *master,
>>>        if (master) {
>>>            ns = mlx5_get_flow_namespace(master,
>>>                             MLX5_FLOW_NAMESPACE_FDB);
>>> +        if (!ns) {
>>> +            mlx5_core_warn(master, "Failed to get flow namespace\n");

Use esw_warn(), for all new instances.