From: Brian King Date: Fri, 17 Nov 2017 17:05:44 +0000 (-0600) Subject: i40e: Use smp_rmb rather than read_barrier_depends X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~7^2~1140 X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/%22mailto:kde%40ewsoftware.de//%22style.css/%22/%22http:/www.example.com/%22mailto:kde%40ewsoftware.de/%22style.css/%22?a=commitdiff_plain;h=e45d7db989db5722fa31541fa8b008ca00385f06;p=linux-4.9.git i40e: Use smp_rmb rather than read_barrier_depends 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 --- diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 31c97e3937a4..2caafebb0295 100644 --- 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(struct i40e_ring *tx_ring, int budget) 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 & diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 6287bf63c43c..c5430394fac9 100644 --- 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 i40e_vsi *vsi, 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)