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* [PATCH] natsemi: add checks for dma mapping errors
@ 2015-12-18 21:55 Alexey Khoroshilov
  2015-12-19  2:36 ` David Miller
  0 siblings, 1 reply; 6+ messages in thread
From: Alexey Khoroshilov @ 2015-12-18 21:55 UTC (permalink / raw)
  To: David S . Miller; +Cc: Alexey Khoroshilov, netdev, linux-kernel, ldv-project

refill_rx() and start_tx() do 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 <khoroshilov@ispras.ru>
---
 drivers/net/ethernet/natsemi/natsemi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/natsemi/natsemi.c b/drivers/net/ethernet/natsemi/natsemi.c
index b83f7c0fcf99..282e59d66a52 100644
--- a/drivers/net/ethernet/natsemi/natsemi.c
+++ b/drivers/net/ethernet/natsemi/natsemi.c
@@ -1937,6 +1937,12 @@ static void refill_rx(struct net_device *dev)
 				break; /* Better luck next round. */
 			np->rx_dma[entry] = pci_map_single(np->pci_dev,
 				skb->data, buflen, PCI_DMA_FROMDEVICE);
+			if (pci_dma_mapping_error(np->pci_dev,
+						  np->rx_dma[entry])) {
+				dev_kfree_skb_any(skb);
+				np->rx_skbuff[entry] = NULL;
+				break; /* Better luck next round. */
+			}
 			np->rx_ring[entry].addr = cpu_to_le32(np->rx_dma[entry]);
 		}
 		np->rx_ring[entry].cmd_status = cpu_to_le32(np->rx_buf_sz);
@@ -2093,6 +2099,10 @@ static netdev_tx_t start_tx(struct sk_buff *skb, struct net_device *dev)
 	np->tx_skbuff[entry] = skb;
 	np->tx_dma[entry] = pci_map_single(np->pci_dev,
 				skb->data,skb->len, PCI_DMA_TODEVICE);
+	if (pci_dma_mapping_error(np->pci_dev, np->tx_dma[entry])) {
+		np->tx_skbuff[entry] = NULL;
+		return NETDEV_TX_BUSY;
+	}
 
 	np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] natsemi: add checks for dma mapping errors
  2015-12-18 21:55 [PATCH] natsemi: add checks for dma mapping errors Alexey Khoroshilov
@ 2015-12-19  2:36 ` David Miller
  2015-12-19 12:06   ` Alexey Khoroshilov
  0 siblings, 1 reply; 6+ messages in thread
From: David Miller @ 2015-12-19  2:36 UTC (permalink / raw)
  To: khoroshilov; +Cc: netdev, linux-kernel, ldv-project

From: Alexey Khoroshilov <khoroshilov@ispras.ru>
Date: Sat, 19 Dec 2015 00:55:37 +0300

> @@ -2093,6 +2099,10 @@ static netdev_tx_t start_tx(struct sk_buff *skb, struct net_device *dev)
>  	np->tx_skbuff[entry] = skb;
>  	np->tx_dma[entry] = pci_map_single(np->pci_dev,
>  				skb->data,skb->len, PCI_DMA_TODEVICE);
> +	if (pci_dma_mapping_error(np->pci_dev, np->tx_dma[entry])) {
> +		np->tx_skbuff[entry] = NULL;
> +		return NETDEV_TX_BUSY;
> +	}
>  
>  	np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
>  

Returning NETDEV_TX_BUSY and freeing the SKB will crash the system.

NETDEV_TX_BUSY is only for buggy drivers that do not manage their
TX ring busy condition correctly, and thus need retries.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] natsemi: add checks for dma mapping errors
  2015-12-19  2:36 ` David Miller
@ 2015-12-19 12:06   ` Alexey Khoroshilov
  2015-12-19 12:13     ` [PATCH v2] " Alexey Khoroshilov
  2015-12-19 17:54     ` [PATCH] " David Miller
  0 siblings, 2 replies; 6+ messages in thread
From: Alexey Khoroshilov @ 2015-12-19 12:06 UTC (permalink / raw)
  To: David Miller; +Cc: netdev, linux-kernel, ldv-project

On 19.12.2015 05:36, David Miller wrote:
> From: Alexey Khoroshilov <khoroshilov@ispras.ru>
> Date: Sat, 19 Dec 2015 00:55:37 +0300
>
>> @@ -2093,6 +2099,10 @@ static netdev_tx_t start_tx(struct sk_buff
*skb, struct net_device *dev)
>>  	np->tx_skbuff[entry] = skb;
>>  	np->tx_dma[entry] = pci_map_single(np->pci_dev,
>>  				skb->data,skb->len, PCI_DMA_TODEVICE);
>> +	if (pci_dma_mapping_error(np->pci_dev, np->tx_dma[entry])) {
>> +		np->tx_skbuff[entry] = NULL;
>> +		return NETDEV_TX_BUSY;
>> +	}
>>
>>  	np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
>>
>
> Returning NETDEV_TX_BUSY and freeing the SKB will crash the system.

I do not quite understand what do you mean by 'freeing the SKB'.
At least the patch left skb untouched.

But I saw such pattern, for example, in
drivers/net/ethernet/freescale/fec_main.c:

	addr = dma_map_single(&fep->pdev->dev, data, size, DMA_TO_DEVICE);
	if (dma_mapping_error(&fep->pdev->dev, addr)) {
		dev_kfree_skb_any(skb);
		if (net_ratelimit())
			netdev_err(ndev, "Tx DMA memory map failed\n");
		return NETDEV_TX_BUSY;
	}

>
> NETDEV_TX_BUSY is only for buggy drivers that do not manage their
> TX ring busy condition correctly, and thus need retries.

Ok, I will replace NETDEV_TX_BUSY by dropping the packet.

--
Alexey


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v2] natsemi: add checks for dma mapping errors
  2015-12-19 12:06   ` Alexey Khoroshilov
@ 2015-12-19 12:13     ` Alexey Khoroshilov
  2015-12-19 17:59       ` David Miller
  2015-12-19 17:54     ` [PATCH] " David Miller
  1 sibling, 1 reply; 6+ messages in thread
From: Alexey Khoroshilov @ 2015-12-19 12:13 UTC (permalink / raw)
  To: David S . Miller; +Cc: Alexey Khoroshilov, netdev, linux-kernel, ldv-project

refill_rx() and start_tx() do 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 <khoroshilov@ispras.ru>
---
 drivers/net/ethernet/natsemi/natsemi.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/ethernet/natsemi/natsemi.c b/drivers/net/ethernet/natsemi/natsemi.c
index b83f7c0fcf99..122c2ee3dfe2 100644
--- a/drivers/net/ethernet/natsemi/natsemi.c
+++ b/drivers/net/ethernet/natsemi/natsemi.c
@@ -1937,6 +1937,12 @@ static void refill_rx(struct net_device *dev)
 				break; /* Better luck next round. */
 			np->rx_dma[entry] = pci_map_single(np->pci_dev,
 				skb->data, buflen, PCI_DMA_FROMDEVICE);
+			if (pci_dma_mapping_error(np->pci_dev,
+						  np->rx_dma[entry])) {
+				dev_kfree_skb_any(skb);
+				np->rx_skbuff[entry] = NULL;
+				break; /* Better luck next round. */
+			}
 			np->rx_ring[entry].addr = cpu_to_le32(np->rx_dma[entry]);
 		}
 		np->rx_ring[entry].cmd_status = cpu_to_le32(np->rx_buf_sz);
@@ -2093,6 +2099,12 @@ static netdev_tx_t start_tx(struct sk_buff *skb, struct net_device *dev)
 	np->tx_skbuff[entry] = skb;
 	np->tx_dma[entry] = pci_map_single(np->pci_dev,
 				skb->data,skb->len, PCI_DMA_TODEVICE);
+	if (pci_dma_mapping_error(np->pci_dev, np->tx_dma[entry])) {
+		np->tx_skbuff[entry] = NULL;
+		dev_kfree_skb_irq(skb);
+		dev->stats.tx_dropped++;
+		return NETDEV_TX_OK;
+	}
 
 	np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] natsemi: add checks for dma mapping errors
  2015-12-19 12:06   ` Alexey Khoroshilov
  2015-12-19 12:13     ` [PATCH v2] " Alexey Khoroshilov
@ 2015-12-19 17:54     ` David Miller
  1 sibling, 0 replies; 6+ messages in thread
From: David Miller @ 2015-12-19 17:54 UTC (permalink / raw)
  To: khoroshilov; +Cc: netdev, linux-kernel, ldv-project

From: Alexey Khoroshilov <khoroshilov@ispras.ru>
Date: Sat, 19 Dec 2015 15:06:45 +0300

> On 19.12.2015 05:36, David Miller wrote:
>> From: Alexey Khoroshilov <khoroshilov@ispras.ru>
>> Date: Sat, 19 Dec 2015 00:55:37 +0300
>>
>>> @@ -2093,6 +2099,10 @@ static netdev_tx_t start_tx(struct sk_buff
> *skb, struct net_device *dev)
>>>  	np->tx_skbuff[entry] = skb;
>>>  	np->tx_dma[entry] = pci_map_single(np->pci_dev,
>>>  				skb->data,skb->len, PCI_DMA_TODEVICE);
>>> +	if (pci_dma_mapping_error(np->pci_dev, np->tx_dma[entry])) {
>>> +		np->tx_skbuff[entry] = NULL;
>>> +		return NETDEV_TX_BUSY;
>>> +	}
>>>
>>>  	np->tx_ring[entry].addr = cpu_to_le32(np->tx_dma[entry]);
>>>
>>
>> Returning NETDEV_TX_BUSY and freeing the SKB will crash the system.
> 
> I do not quite understand what do you mean by 'freeing the SKB'.
> At least the patch left skb untouched.

Sorry, I misread your patch, I thought I saw a kfree there but
obviously there isn't.

>> NETDEV_TX_BUSY is only for buggy drivers that do not manage their
>> TX ring busy condition correctly, and thus need retries.
> 
> Ok, I will replace NETDEV_TX_BUSY by dropping the packet.

Thanks.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v2] natsemi: add checks for dma mapping errors
  2015-12-19 12:13     ` [PATCH v2] " Alexey Khoroshilov
@ 2015-12-19 17:59       ` David Miller
  0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2015-12-19 17:59 UTC (permalink / raw)
  To: khoroshilov; +Cc: netdev, linux-kernel, ldv-project

From: Alexey Khoroshilov <khoroshilov@ispras.ru>
Date: Sat, 19 Dec 2015 15:13:49 +0300

> refill_rx() and start_tx() do 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 <khoroshilov@ispras.ru>

Applied, thanks.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2015-12-19 17:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-18 21:55 [PATCH] natsemi: add checks for dma mapping errors Alexey Khoroshilov
2015-12-19  2:36 ` David Miller
2015-12-19 12:06   ` Alexey Khoroshilov
2015-12-19 12:13     ` [PATCH v2] " Alexey Khoroshilov
2015-12-19 17:59       ` David Miller
2015-12-19 17:54     ` [PATCH] " David Miller

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