| Message ID | 20100220034419.31030.5083.stgit@localhost.localdomain |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Date: Fri, 19 Feb 2010 19:44:42 -0800 > From: Milton Miller <miltonm@bga.com> > > The PowerPC architecture does not require loads to independent bytes to be > ordered without adding an explicit barrier. > > In ixgbe_clean_rx_irq we load the status bit then load the packet data. > With packet split disabled if these loads go out of order we get a > stale packet, but we will notice the bad sequence numbers and drop it. > > The problem occurs with packet split enabled where the TCP/IP header and data > are in different descriptors. If the reads go out of order we may have data > that doesn't match the TCP/IP header. Since we use hardware checksumming this > bad data is never verified and it makes it all the way to the application. > > This bug was found during stress testing and adding this barrier has been shown > to fix it. > > Signed-off-by: Milton Miller <miltonm@bga.com> > Signed-off-by: Anton Blanchard <anton@samba.org> > Acked-by: Don Skidmore <donald.c.skidmore@intel.com> > Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index 43a8de3..3308790 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -849,6 +849,7 @@ static bool ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, break; (*work_done)++; + rmb(); /* read descriptor and rx_buffer_info after status DD */ if (rx_ring->flags & IXGBE_RING_RX_PS_ENABLED) { hdr_info = le16_to_cpu(ixgbe_get_hdr_info(rx_desc)); len = (hdr_info & IXGBE_RXDADV_HDRBUFLEN_MASK) >>