Messages in this thread Patch in this message | | | Date | Fri, 18 Nov 2022 19:11:28 +0200 | From | Leon Romanovsky <> | Subject | Re: [PATCH net] sfc: fix potential memleak in __ef100_hard_start_xmit() |
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On Fri, Nov 18, 2022 at 09:15:43AM +0000, Martin Habets wrote: > On Thu, Nov 17, 2022 at 03:05:27PM +0200, Leon Romanovsky wrote: > > On Thu, Nov 17, 2022 at 08:41:52PM +0800, Zhang Changzhong wrote: > > > > > > > > > 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@huawei.com> > > > >> --- > > > >> 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. > > > > Please take a look __ef100_enqueue_skb() and see if it frees SKB on > > error or not. If not, please fix it. > > That function looks ok to me, but I appreciate the extra eyes on it.
__ef100_enqueue_skb() has the following check in error path:
498 err: 499 efx_enqueue_unwind(tx_queue, old_insert_count); 500 if (!IS_ERR_OR_NULL(skb)) 501 dev_kfree_skb_any(skb); 502 The issue is that skb is never error or null here and this "if" is actually always true and can be deleted.
Thanks
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