Re: [PATCH net] sfc: fix potential memleak in __ef100_hard_start_xmit()

From: Zhang Changzhong
Date: Thu Nov 17 2022 - 07:45:33 EST




On 2022/11/17 19:36, Leon Romanovsky wrote:
> On Thu, Nov 17, 2022 at 03:50:09PM +0800, Zhang Changzhong wrote:
>> The __ef100_hard_start_xmit() returns NETDEV_TX_OK without freeing skb
>> in error handling case, add dev_kfree_skb_any() to fix it.
>>
>> Fixes: 51b35a454efd ("sfc: skeleton EF100 PF driver")
>> Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
>> ---
>> drivers/net/ethernet/sfc/ef100_netdev.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/net/ethernet/sfc/ef100_netdev.c b/drivers/net/ethernet/sfc/ef100_netdev.c
>> index 88fa295..ddcc325 100644
>> --- a/drivers/net/ethernet/sfc/ef100_netdev.c
>> +++ b/drivers/net/ethernet/sfc/ef100_netdev.c
>> @@ -218,6 +218,7 @@ netdev_tx_t __ef100_hard_start_xmit(struct sk_buff *skb,
>> skb->len, skb->data_len, channel->channel);
>> if (!efx->n_channels || !efx->n_tx_channels || !channel) {
>> netif_stop_queue(net_dev);
>> + dev_kfree_skb_any(skb);
>> goto err;
>> }
>
> ef100 doesn't release in __ef100_enqueue_skb() either. SKB shouldn't be
> NULL or ERR at this stage.

SKB shouldn't be NULL or ERR, so it can be freed. But this code looks weird.

>
> diff --git a/drivers/net/ethernet/sfc/ef100_tx.c b/drivers/net/ethernet/sfc/ef100_tx.c
> index 29ffaf35559d..426706b91d02 100644
> --- a/drivers/net/ethernet/sfc/ef100_tx.c
> +++ b/drivers/net/ethernet/sfc/ef100_tx.c
> @@ -497,7 +497,7 @@ int __ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
>
> err:
> efx_enqueue_unwind(tx_queue, old_insert_count);
> - if (!IS_ERR_OR_NULL(skb))
> + if (rc)
> dev_kfree_skb_any(skb);
>
> /* If we're not expecting another transmit and we had something to push
>
>
>>
>> --
>> 2.9.5
>>
> .
>