[PATCH 4.14 092/146] net/mlx5e: Prevent possible races in VXLAN control flow

Greg Kroah-Hartman
2018-01-01T14:44:20Z

From: Gal Pressman <galp@mellanox.com>

[ Upstream commit 0c1cc8b2215f5122ca614b5adca60346018758c3 ]

When calling add/remove VXLAN port, a lock must be held in order to
prevent race scenarios when more than one add/remove happens at the
same time.
Fix by holding our state_lock (mutex) as done by all other parts of the
driver.
Note that the spinlock protecting the radix-tree is still needed in
order to synchronize radix-tree access from softirq context.

Fixes: b3f63c3d5e2c ("net/mlx5e: Add netdev support for VXLAN tunneling")
Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/vxlan.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/vxlan.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/vxlan.c
@@ -88,6 +88,7 @@ static void mlx5e_vxlan_add_port(struct
struct mlx5e_vxlan *vxlan;
int err;

+ mutex_lock(&priv->state_lock);
vxlan = mlx5e_vxlan_lookup_port(priv, port);
if (vxlan) {
atomic_inc(&vxlan->refcount);
@@ -117,6 +118,7 @@ err_free:
err_delete_port:
mlx5e_vxlan_core_del_port_cmd(priv->mdev, port);
free_work:
+ mutex_unlock(&priv->state_lock);
kfree(vxlan_work);
}

@@ -130,6 +132,7 @@ static void mlx5e_vxlan_del_port(struct
struct mlx5e_vxlan *vxlan;
bool remove = false;

+ mutex_lock(&priv->state_lock);
spin_lock_bh(&vxlan_db->lock);
vxlan = radix_tree_lookup(&vxlan_db->tree, port);
if (!vxlan)
@@ -147,6 +150,7 @@ out_unlock:
mlx5e_vxlan_core_del_port_cmd(priv->mdev, port);
kfree(vxlan);
}
+ mutex_unlock(&priv->state_lock);
kfree(vxlan_work);
}