From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934097AbdK1KwR (ORCPT ); Tue, 28 Nov 2017 05:52:17 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35500 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934078AbdK1KwO (ORCPT ); Tue, 28 Nov 2017 05:52:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brian King , Jesse Brandeburg , Andrew Bowers , Jeff Kirsher Subject: [PATCH 4.9 071/138] i40e: Use smp_rmb rather than read_barrier_depends Date: Tue, 28 Nov 2017 11:22:52 +0100 Message-Id: <20171128100550.217415868@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171128100544.706504901@linuxfoundation.org> References: <20171128100544.706504901@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brian King 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. Signed-off-by: Brian King Acked-by: Jesse Brandeburg Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher Signed-off-by: Greg Kroah-Hartman --- 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(-) --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -3604,7 +3604,7 @@ 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 & --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -679,7 +679,7 @@ 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)