Re: [PATCH net-next] net/mlx5: HWS, Add an error check in hws_bwc_rule_complex_hash_node_get()

[Yevgeny Kliteynik <kliteyn@nvidia.com>]

On 28-May-25 11:12, Dan Carpenter wrote:
> The rhashtable_lookup_get_insert_fast() function inserts an object into
> the hashtable.  If the object was already present in the table it
> returns a pointer to the original object.  If the object wasn't there
> it returns NULL.  If there was an allocation error or some other kind
> of failure, it returns an error pointer.
> 
> This caller needs to check for error pointers to avoid an error pointer
> dereference.  Add the check.
> 
> Fixes: 17e0accac577 ("net/mlx5: HWS, support complex matchers")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>   .../net/ethernet/mellanox/mlx5/core/steering/hws/bwc_complex.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc_complex.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc_complex.c
> index 5d30c5b094fc..6ae362fe2f36 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc_complex.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc_complex.c
> @@ -1094,6 +1094,9 @@ hws_bwc_rule_complex_hash_node_get(struct mlx5hws_bwc_rule *bwc_rule,
>   	old_node = rhashtable_lookup_get_insert_fast(refcount_hash,
>   						     &node->hash_node,
>   						     hws_refcount_hash);
> +	if (IS_ERR(old_node))
> +		return PTR_ERR(old_node);
> +

Agree with the need to check IS_ERR, but error flow is missing here.
Need to free the previously allocated IDA and node.

-- YK

>   	if (old_node) {
>   		/* Rule with the same tag already exists - update refcount */
>   		refcount_inc(&old_node->refcount);