4.15-stable review patch. If anyone has any objections, please let me know.
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From: Emil Tantilov emil.s.tantilov@intel.com
commit 0c5661ecc5dd7ce296870a3eb7b62b1b280a5e89 upstream.
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@vger.kernel.org Reported-by: Ambarish Soman asoman@redhat.com Suggested-by: Alexander Duyck alexander.h.duyck@intel.com Signed-off-by: Emil Tantilov emil.s.tantilov@intel.com Tested-by: Andrew Bowers andrewx.bowers@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1878,6 +1878,14 @@ static void ixgbe_dma_sync_frag(struct i 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];