Re: [net] ixgbe: fix crash in build_skb Rx code path

2018-02-26 Thread David Miller
From: Jeff Kirsher 
Date: Fri, 23 Feb 2018 12:39:41 -0800

> From: Emil Tantilov 
> 
> Add check for build_skb enabled ring in ixgbe_dma_sync_frag().
> In that case &skb_shinfo(skb)->frags[0] may not always be set which
> can lead to a crash. Instead we derive the page offset from skb->data.
> 
> Fixes: 42073d91a214
> ("ixgbe: Have the CPU take ownership of the buffers sooner")
> CC: stable 
> Reported-by: Ambarish Soman 
> Suggested-by: Alexander Duyck 
> Signed-off-by: Emil Tantilov 
> Tested-by: Andrew Bowers 
> Signed-off-by: Jeff Kirsher 

Applied, thanks Jeff.


[net] ixgbe: fix crash in build_skb Rx code path

2018-02-23 Thread Jeff Kirsher
From: Emil Tantilov 

Add check for build_skb enabled ring in ixgbe_dma_sync_frag().
In that case &skb_shinfo(skb)->frags[0] may not always be set which
can lead to a crash. Instead we derive the page offset from skb->data.

Fixes: 42073d91a214
("ixgbe: Have the CPU take ownership of the buffers sooner")
CC: stable 
Reported-by: Ambarish Soman 
Suggested-by: Alexander Duyck 
Signed-off-by: Emil Tantilov 
Tested-by: Andrew Bowers 
Signed-off-by: Jeff Kirsher 
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 0da5aa2c8aba..9fc063af233c 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1888,6 +1888,14 @@ static void ixgbe_dma_sync_frag(struct ixgbe_ring 
*rx_ring,
 ixgbe_rx_pg_size(rx_ring),
 DMA_FROM_DEVICE,
 IXGBE_RX_DMA_ATTR);
+   } else if (ring_uses_build_skb(rx_ring)) {
+   unsigned long offset = (unsigned long)(skb->data) & ~PAGE_MASK;
+
+   dma_sync_single_range_for_cpu(rx_ring->dev,
+ IXGBE_CB(skb)->dma,
+ offset,
+ skb_headlen(skb),
+ DMA_FROM_DEVICE);
} else {
struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
 
-- 
2.14.3