Re: [PATCH net] net/mlx5: DR, fix memory leak in mlx5dr_cmd_create_reformat_ctx

[Leon Romanovsky <leon@kernel.org>]

On Tue, Jul 04, 2023 at 03:40:44PM +0100, Simon Horman wrote:
> On Tue, Jul 04, 2023 at 11:33:08AM +0800, Zhengchao Shao wrote:
> > when mlx5_cmd_exec failed in mlx5dr_cmd_create_reformat_ctx, the memory
> > pointed by 'in' is not released, which will cause memory leak. Move memory
> > release after mlx5_cmd_exec.
> > 
> > Fixes: 1d9186476e12 ("net/mlx5: DR, Add direct rule command utilities")
> > Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
> > ---
> >  drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> > index 7491911ebcb5..cf5820744e99 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> > @@ -563,11 +563,11 @@ int mlx5dr_cmd_create_reformat_ctx(struct mlx5_core_dev *mdev,
> >  		memcpy(pdata, reformat_data, reformat_size);
> >  
> >  	err = mlx5_cmd_exec(mdev, in, inlen, out, sizeof(out));
> > +	kvfree(in);
> >  	if (err)
> >  		return err;
> >  
> >  	*reformat_id = MLX5_GET(alloc_packet_reformat_context_out, out, packet_reformat_id);
> > -	kvfree(in);
> >  
> >  	return err;
> >  }
> 
> Hi Zhengchao Shao,
> 
> I agree this is a correct fix.
> However, I think a more idiomatic approach to this problem
> would be to use a goto label. Something like this (completely untested!).

Thanks, your change looks more natural to me.

> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> index 7491911ebcb5..8c2a34a0d6be 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_cmd.c
> @@ -564,11 +564,12 @@ int mlx5dr_cmd_create_reformat_ctx(struct mlx5_core_dev *mdev,
>  
>  	err = mlx5_cmd_exec(mdev, in, inlen, out, sizeof(out));
>  	if (err)
> -		return err;
> +		goto err_free_in;
>  
>  	*reformat_id = MLX5_GET(alloc_packet_reformat_context_out, out, packet_reformat_id);
> -	kvfree(in);
>  
> +err_free_in:
> +	kvfree(in);
>  	return err;
>  }
>