Seen in RH 2.6.32 and applies fine to latest Debian 2.6.32. davem, please ack for longterm 2.6.32 and 2.6.33 inclusion?
thank you. ----- Forwarded message from Linux Kernel Mailing List <[email protected]> ----- Date: Tue, 2 Mar 2010 20:11:12 GMT From: Linux Kernel Mailing List <[email protected]> To: [email protected] Subject: ixgbe: prevent speculative processing of descriptors before ready Gitweb: http://git.kernel.org/linus/3c945e5b3719bcc18c6ddd31bbcae8ef94f3d19a Commit: 3c945e5b3719bcc18c6ddd31bbcae8ef94f3d19a Parent: 06c92ee6384c33dbb6e313c66272181db70abbb0 Author: Milton Miller <[email protected]> AuthorDate: Fri Feb 19 17:44:42 2010 +0000 Committer: David S. Miller <[email protected]> CommitDate: Mon Feb 22 15:45:32 2010 -0800 ixgbe: prevent speculative processing of descriptors before ready 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 <[email protected]> Signed-off-by: Anton Blanchard <[email protected]> Acked-by: Don Skidmore <[email protected]> Signed-off-by: Jeff Kirsher <[email protected]> Signed-off-by: David S. Miller <[email protected]> --- drivers/net/ixgbe/ixgbe_main.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) 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) >> -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html ----- End forwarded message ----- _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
