[PATCH 4.9 51/75] net/mlx5e: Prevent possible races in VXLAN control flow

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gal Pressman <g...@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 <g...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gre...@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);
 }