From fe1ff29dd4989f6371e8d78bc340f596f4a78e04 Mon Sep 17 00:00:00 2001 From: Shani Michaelli Date: Wed, 14 May 2014 12:15:15 +0300 Subject: [PATCH] net/mlx4_en: Protect MAC address modification with the state_lock mutex This Patches solves an issue that could raise when modifying the device's MAC. It occurs due to a simultaneous access to priv->mac_hash from two contexts. The buggy scenario described below: Context 1: copy the new mac address to the dev->dev_addr field. Context 2: mlx4_en_do_uc_filter removes prev_mac entry from the mac_hash db since it is not in dev->uc and not equal to dev->dev_addr. Context 1: mlx4_en_do_set_mac() calls mlx4_en_replace_mac() to replace prev_mac with dev_addr but it fails to update the mac_hash db since it no longer contains prev_mac, therefore it returns with an error. The fix is to prevent mlx4_en_do_uc_filter from being executed by both of the context 1 calls described above, This is done by putting them both under the mdev->state_lock lock, it will solve this issue since mlx4_en_do_uc_filter is already protected by the mdev->state_lock. Reviewed-by: Eyal Perry Signed-off-by: Shani Michaeli Signed-off-by: Amir Vadai Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c index c0247945d835..8e8fb69fa871 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c @@ -789,9 +789,8 @@ static int mlx4_en_set_mac(struct net_device *dev, void *addr) if (!is_valid_ether_addr(saddr->sa_data)) return -EADDRNOTAVAIL; - memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN); - mutex_lock(&mdev->state_lock); + memcpy(dev->dev_addr, saddr->sa_data, ETH_ALEN); err = mlx4_en_do_set_mac(priv); mutex_unlock(&mdev->state_lock); -- 2.20.1