Re: [PATCH] net: natsemi: ns83820: add checks for dma mapping error

[David Miller]

From: Alexey Khoroshilov 
Date: Sat, 15 Apr 2017 01:50:50 +0300

> @@ -1136,6 +1141,10 @@ static netdev_tx_t ns83820_hard_start_xmit(struct 
> sk_buff *skb,
>   if (nr_frags)
>   len -= skb->data_len;
>   buf = pci_map_single(dev->pci_dev, skb->data, len, PCI_DMA_TODEVICE);
> + if (pci_dma_mapping_error(dev->pci_dev, buf)) {
> + dev_kfree_skb_any(skb);
> + return NETDEV_TX_OK;
> + }
>  
>   first_desc = dev->tx_descs + (free_idx * DESC_SIZE);
>  

You need to also add this check for the skb_map_dma_frag() calls below
this line, and therefore you'll need to add unwind on such a failure.

[PATCH] net: natsemi: ns83820: add checks for dma mapping error

[Alexey Khoroshilov]

The driver does not check if mapping dma memory succeed.
The patch adds the checks and failure handling.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov 
---
 drivers/net/ethernet/natsemi/ns83820.c | 13 +++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/natsemi/ns83820.c 
b/drivers/net/ethernet/natsemi/ns83820.c
index 729095db3e08..7d6d692ebb92 100644
--- a/drivers/net/ethernet/natsemi/ns83820.c
+++ b/drivers/net/ethernet/natsemi/ns83820.c
@@ -534,14 +534,19 @@ static inline int ns83820_add_rx_skb(struct ns83820 *dev, 
struct sk_buff *skb)
);
 #endif
 
+   buf = pci_map_single(dev->pci_dev, skb->data,
+REAL_RX_BUF_SIZE, PCI_DMA_FROMDEVICE);
+   if (pci_dma_mapping_error(dev->pci_dev, buf)) {
+   kfree_skb(skb);
+   return 1;
+   }
+
sg = dev->rx_info.descs + (next_empty * DESC_SIZE);
BUG_ON(NULL != dev->rx_info.skbs[next_empty]);
dev->rx_info.skbs[next_empty] = skb;
 
dev->rx_info.next_empty = (next_empty + 1) % NR_RX_DESC;
cmdsts = REAL_RX_BUF_SIZE | CMDSTS_INTR;
-   buf = pci_map_single(dev->pci_dev, skb->data,
-REAL_RX_BUF_SIZE, PCI_DMA_FROMDEVICE);
build_rx_desc(dev, sg, 0, buf, cmdsts, 0);
/* update link of previous rx */
if (likely(next_empty != dev->rx_info.next_rx))
@@ -1136,6 +1141,10 @@ static netdev_tx_t ns83820_hard_start_xmit(struct 
sk_buff *skb,
if (nr_frags)
len -= skb->data_len;
buf = pci_map_single(dev->pci_dev, skb->data, len, PCI_DMA_TODEVICE);
+   if (pci_dma_mapping_error(dev->pci_dev, buf)) {
+   dev_kfree_skb_any(skb);
+   return NETDEV_TX_OK;
+   }
 
first_desc = dev->tx_descs + (free_idx * DESC_SIZE);
 
-- 
2.7.4