e1000e: stop cleaning when we reach tx_ring->next_to_use

commit dac876193cd79ced36d0462749ea47c05844fb49 upstream.

Tx ring buffers after tx_ring->next_to_use are volatile and could
change, possibly causing a crash.  Stop cleaning when we hit
tx_ring->next_to_use.

Signed-off-by: Terry Loftin <terry.loftin@hp.com>
Acked-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Matthew Burgess <matthew@linuxfromscratch.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 57f149b75fbe9d07f4b5e05e3e14c919d4987461..4d353d25d60b288bab79ca08cc11b34c2eb0c561 100644 (file)
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -660,6 +660,8 @@ static bool e1000_clean_tx_irq(struct e1000_adapter *adapter)
                                i = 0;
                }
 
+               if (i == tx_ring->next_to_use)
+                       break;
                eop = tx_ring->buffer_info[i].next_to_watch;
                eop_desc = E1000_TX_DESC(*tx_ring, eop);
        }