This is a note to let you know that I've just added the patch titled

igb: Use smp_rmb rather than read_barrier_depends

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: igb-use-smp_rmb-rather-than-read_barrier_depends.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From c4cb99185b4cc96c0a1c70104dc21ae14d7e7f28 Mon Sep 17 00:00:00 2001

From: Brian King brking@linux.vnet.ibm.com Date: Fri, 17 Nov 2017 11:05:47 -0600 Subject: igb: Use smp_rmb rather than read_barrier_depends

From: Brian King brking@linux.vnet.ibm.com

commit c4cb99185b4cc96c0a1c70104dc21ae14d7e7f28 upstream.

The original issue being fixed in this patch was seen with the ixgbe driver, but the same issue exists with igb as well, as the code is very similar. read_barrier_depends is not sufficient to ensure loads following it are not speculatively loaded out of order by the CPU, which can result in stale data being loaded, causing potential system crashes.

Signed-off-by: Brian King brking@linux.vnet.ibm.com Acked-by: Jesse Brandeburg jesse.brandeburg@intel.com Tested-by: Aaron Brown aaron.f.brown@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/net/ethernet/intel/igb/igb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -6433,7 +6433,7 @@ static bool igb_clean_tx_irq(struct igb_ break;

/* prevent any other reads prior to eop_desc */ - read_barrier_depends(); + smp_rmb();

/* if DD is not set pending work has not been completed */ if (!(eop_desc->wb.status & cpu_to_le32(E1000_TXD_STAT_DD)))

Patches currently in stable-queue which might be from brking@linux.vnet.ibm.com are

queue-4.4/i40evf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-4.4/igb-use-smp_rmb-rather-than-read_barrier_depends.patch queue-4.4/ixgbevf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-4.4/igbvf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-4.4/fm10k-use-smp_rmb-rather-than-read_barrier_depends.patch queue-4.4/ixgbe-fix-skb-list-corruption-on-power-systems.patch queue-4.4/i40e-use-smp_rmb-rather-than-read_barrier_depends.patch