The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 0c5661ecc5dd7ce296870a3eb7b62b1b280a5e89 Mon Sep 17 00:00:00 2001
From: Emil Tantilov <emil.s.tantilov@xxxxxxxxx>
Date: Fri, 23 Feb 2018 12:39:41 -0800
Subject: [PATCH] ixgbe: fix crash in build_skb Rx code path
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 <stable@xxxxxxxxxxxxxxx>
Reported-by: Ambarish Soman <asoman@xxxxxxxxxx>
Suggested-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
Signed-off-by: Emil Tantilov <emil.s.tantilov@xxxxxxxxx>
Tested-by: Andrew Bowers <andrewx.bowers@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
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];