Re: [PATCH v2] qlcnic: fix a memory leak in qlcnic_sriov_set_guest_vlan_mode()

[Paolo Abeni <pabeni@redhat.com>]

On 3/5/25 11:09 AM, Haoxiang Li wrote:
> Add qlcnic_sriov_free_vlans() to free the memory allocated by
> qlcnic_sriov_alloc_vlans() if qlcnic_sriov_alloc_vlans() fails
> or "sriov->allowed_vlans" fails to be allocated.
> 
> Fixes: 91b7282b613d ("qlcnic: Support VLAN id config.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
> ---
> Changes in v2:
> - Add qlcnic_sriov_free_vlans() if qlcnic_sriov_alloc_vlans() fails.
> - Modify the patch description.
> vf_info was allocated by kcalloc, no need to do more checks cause
> kfree(NULL) is safe. Thanks, Paolo! 
> ---
>  drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
> index f9dd50152b1e..0dd9d7cb1de9 100644
> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
> @@ -446,16 +446,20 @@ static int qlcnic_sriov_set_guest_vlan_mode(struct qlcnic_adapter *adapter,
>  		 sriov->num_allowed_vlans);
>  
>  	ret = qlcnic_sriov_alloc_vlans(adapter);
> -	if (ret)
> +	if (ret) {
> +		qlcnic_sriov_free_vlans(adapter);

I'm sorry for the lack of clarity in my previous reply. I think it would
be better to do this cleanup inside qlcnic_sriov_alloc_vlans(), so that
on error it returns with no vlan allocated.

There is another caller of qlcnic_sriov_alloc_vlans() which AFAICS still
leak memory on error. Handling the deallocation in
qlcnic_sriov_alloc_vlans() will address even that caller.

Thanks,

Paolo