Re: [net PATCH] atl1c: Fix misuse of netdev_alloc_skb in refilling rx ring

Eric Dumazet
2013-07-28T20:08:33Z

On Sun, 2013-07-28 at 12:21 -0700, Eric Dumazet wrote:

>
> btw, this driver leaks skb horribly in this error path :
>
> if (rrs->word3 & (RRS_RX_ERR_SUM | RRS_802_3_LEN_ERR)) {
> atl1c_clean_rfd(rfd_ring, rrs, rfd_num);
> if (netif_msg_rx_err(adapter))
> dev_warn(&pdev->dev,
> "wrong packet! rrs word3 is %x\n",
> rrs->word3);
> continue;
> }

Possible fix would be :

diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
index 786a874..e815c23 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
@@ -1729,11 +1729,16 @@ static void atl1c_clean_rfd(struct atl1c_rfd_ring *rfd_ring,
u16 i;
u16 rfd_index;
struct atl1c_buffer *buffer_info = rfd_ring->buffer_info;
+ struct sk_buff *skb;

rfd_index = (rrs->word0 >> RRS_RX_RFD_INDEX_SHIFT) &
RRS_RX_RFD_INDEX_MASK;
for (i = 0; i < num; i++) {
- buffer_info[rfd_index].skb = NULL;
+ skb = buffer_info[rfd_index].skb;
+ if (skb) {
+ kfree_skb(skb);
+ buffer_info[rfd_index].skb = NULL;
+ }
ATL1C_SET_BUFFER_STATE(&buffer_info[rfd_index],
ATL1C_BUFFER_FREE);
if (++rfd_index == rfd_ring->count)
@@ -1793,6 +1798,7 @@ rrs_checked:
pci_unmap_single(pdev, buffer_info->dma,
buffer_info->length, PCI_DMA_FROMDEVICE);
skb = buffer_info->skb;
+ buffer_info->skb = NULL;
} else {
/* TODO */
if (netif_msg_rx_err(adapter))