Patch "i40e: Use smp_rmb rather than read_barrier_depends" has been added to the 3.18-stable tree

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

i40e: Use smp_rmb rather than read_barrier_depends

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
i40e-use-smp_rmb-rather-than-read_barrier_depends.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Brian King <[email protected]>
Date: Fri, 17 Nov 2017 11:05:44 -0600
Subject: i40e: Use smp_rmb rather than read_barrier_depends

From: Brian King <[email protected]>

commit 52c6912fde0133981ee50ba08808f257829c4c93 upstream.

The original issue being fixed in this patch was seen with the ixgbe driver, but the same issue exists with i40e 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.

---
 drivers/net/ethernet/intel/i40e/i40e_main.c |    2 +-
 drivers/net/ethernet/intel/i40e/i40e_txrx.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

@@ -3214,7 +3214,7 @@ static bool i40e_clean_fdir_tx_irq(struc
 			break;
 
 		/* prevent any other reads prior to eop_desc */
-		read_barrier_depends();
+		smp_rmb();
 
 		/* if the descriptor isn't done, no work yet to do */
 		if (!(eop_desc->cmd_type_offset_bsz &

@@ -688,7 +688,7 @@ static bool i40e_clean_tx_irq(struct i40
 			break;
 
 		/* prevent any other reads prior to eop_desc */
-		read_barrier_depends();
+		smp_rmb();
 
 		/* we have caught up to head, no work left to do */
 		if (tx_head == tx_desc)

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/i40evf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-3.18/igb-use-smp_rmb-rather-than-read_barrier_depends.patch queue-3.18/ixgbevf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-3.18/igbvf-use-smp_rmb-rather-than-read_barrier_depends.patch queue-3.18/fm10k-use-smp_rmb-rather-than-read_barrier_depends.patch queue-3.18/ixgbe-fix-skb-list-corruption-on-power-systems.patch queue-3.18/i40e-use-smp_rmb-rather-than-read_barrier_depends.patch