Re: [PATCH net] net: stmmac: selftests: fix potential memleak in stmmac_test_arpoffload()

[Zhang Changzhong <zhangchangzhong@huawei.com>]

On 2022/12/7 17:12, Leon Romanovsky wrote:
> On Wed, Dec 07, 2022 at 04:31:59PM +0800, Zhang Changzhong wrote:
>> The skb allocated by stmmac_test_get_arp_skb() hasn't been released in
>> some error handling case, which will lead to a memory leak. Fix this up
>> by adding kfree_skb() to release skb.
>>
>> Compile tested only.
>>
>> Fixes: 5e3fb0a6e2b3 ("net: stmmac: selftests: Implement the ARP Offload test")
>> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
>> ---
>>  drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> index 49af7e7..687f43c 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_selftests.c
>> @@ -1654,12 +1654,16 @@ static int stmmac_test_arpoffload(struct stmmac_priv *priv)
>>  	}
>>  
>>  	ret = stmmac_set_arp_offload(priv, priv->hw, true, ip_addr);
>> -	if (ret)
>> +	if (ret) {
>> +		kfree_skb(skb);
>>  		goto cleanup;
>> +	}
>>  
>>  	ret = dev_set_promiscuity(priv->dev, 1);
>> -	if (ret)
>> +	if (ret) {
>> +		kfree_skb(skb);
>>  		goto cleanup;
>> +	}
>>  
>>  	ret = dev_direct_xmit(skb, 0);
>>  	if (ret)
> 
> You should release skb here too. So the better patch will be to write
> something like that:
> 

Hi Leon,

Thanks for your review, but I don't think we need release skb here,
because dev_direct_xmit() is responsible for freeing it.

Regards,
Changzhong

> cleanup:
>   stmmac_set_arp_offload(priv, priv->hw, false, 0x0);
>   if (ret)
>   	kfree_skb(skb);
>> Thanks
> 
>> -- 
>> 2.9.5
>>
> .
>