[PATCH] i40e: fix mac filter delete when setting mac address

[PATCH] i40e: fix mac filter delete when setting mac address

[Stefan Assmann]

A previous commit moved the ether_addr_copy() in i40e_set_mac() before
the mac filter del/add to avoid a race. However it wasn't taken into
account that this alters the mac address being handed to
i40e_del_mac_filter().

Also changed i40e_add_mac_filter() to operate on netdev->dev_addr,
hopefully that makes the code easier to read.

Fixes: 458867b2ca0c ("i40e: don't remove netdev->dev_addr when syncing uc list")

Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 6d5b13f69dec..901ef799d2ad 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -1546,17 +1546,17 @@ static int i40e_set_mac(struct net_device *netdev, void *p)
 		netdev_info(netdev, "set new mac address %pM\n", addr->sa_data);
 
 	/* Copy the address first, so that we avoid a possible race with
-	 * .set_rx_mode(). If we copy after changing the address in the filter
-	 * list, we might open ourselves to a narrow race window where
-	 * .set_rx_mode could delete our dev_addr filter and prevent traffic
-	 * from passing.
+	 * .set_rx_mode().
+	 * - Remove old address from MAC filter
+	 * - Copy new address
+	 * - Add new address to MAC filter
 	 */
-	ether_addr_copy(netdev->dev_addr, addr->sa_data);
-
 	spin_lock_bh(&vsi->mac_filter_hash_lock);
 	i40e_del_mac_filter(vsi, netdev->dev_addr);
-	i40e_add_mac_filter(vsi, addr->sa_data);
+	ether_addr_copy(netdev->dev_addr, addr->sa_data);
+	i40e_add_mac_filter(vsi, netdev->dev_addr);
 	spin_unlock_bh(&vsi->mac_filter_hash_lock);
+
 	if (vsi->type == I40E_VSI_MAIN) {
 		i40e_status ret;
 
-- 
2.19.2

RE: [Intel-wired-lan] [PATCH] i40e: fix mac filter delete when setting mac address

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Stefan Assmann
> Sent: Tuesday, December 4, 2018 6:19 AM
> To: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org; davem@davemloft.net; sassmann@kpanic.de
> Subject: [Intel-wired-lan] [PATCH] i40e: fix mac filter delete when setting
> mac address
> 
> A previous commit moved the ether_addr_copy() in i40e_set_mac() before
> the mac filter del/add to avoid a race. However it wasn't taken into account
> that this alters the mac address being handed to i40e_del_mac_filter().
> 
> Also changed i40e_add_mac_filter() to operate on netdev->dev_addr,
> hopefully that makes the code easier to read.
> 
> Fixes: 458867b2ca0c ("i40e: don't remove netdev->dev_addr when syncing
> uc list")
> 
> Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>

RE: [PATCH] i40e: fix mac filter delete when setting mac address

[Keller, Jacob E]

> -----Original Message-----
> From: Stefan Assmann [mailto:sassmann@kpanic.de]
> Sent: Tuesday, December 04, 2018 6:19 AM
> To: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org; davem@davemloft.net; Kirsher, Jeffrey T
> <jeffrey.t.kirsher@intel.com>; Keller, Jacob E <jacob.e.keller@intel.com>;
> sassmann@kpanic.de
> Subject: [PATCH] i40e: fix mac filter delete when setting mac address
> 
> A previous commit moved the ether_addr_copy() in i40e_set_mac() before
> the mac filter del/add to avoid a race. However it wasn't taken into
> account that this alters the mac address being handed to
> i40e_del_mac_filter().

Woops!

> 
> Also changed i40e_add_mac_filter() to operate on netdev->dev_addr,
> hopefully that makes the code easier to read.
> 

Makes sense.

> Fixes: 458867b2ca0c ("i40e: don't remove netdev->dev_addr when syncing uc list")
> 

Good catch. This looks correct to me.

Acked-by: Jacob Keller <jacob.e.keller@intel.com>

> Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c
> b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 6d5b13f69dec..901ef799d2ad 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -1546,17 +1546,17 @@ static int i40e_set_mac(struct net_device *netdev, void
> *p)
>  		netdev_info(netdev, "set new mac address %pM\n", addr->sa_data);
> 
>  	/* Copy the address first, so that we avoid a possible race with
> -	 * .set_rx_mode(). If we copy after changing the address in the filter
> -	 * list, we might open ourselves to a narrow race window where
> -	 * .set_rx_mode could delete our dev_addr filter and prevent traffic
> -	 * from passing.
> +	 * .set_rx_mode().
> +	 * - Remove old address from MAC filter
> +	 * - Copy new address
> +	 * - Add new address to MAC filter
>  	 */
> -	ether_addr_copy(netdev->dev_addr, addr->sa_data);
> -
>  	spin_lock_bh(&vsi->mac_filter_hash_lock);
>  	i40e_del_mac_filter(vsi, netdev->dev_addr);
> -	i40e_add_mac_filter(vsi, addr->sa_data);
> +	ether_addr_copy(netdev->dev_addr, addr->sa_data);
> +	i40e_add_mac_filter(vsi, netdev->dev_addr);
>  	spin_unlock_bh(&vsi->mac_filter_hash_lock);
> +
>  	if (vsi->type == I40E_VSI_MAIN) {
>  		i40e_status ret;
> 
> --
> 2.19.2