mlxsw: core: Unpublish devlink parameters during reload

The devlink parameter "acl_region_rehash_interval" is a runtime
parameter whose value is stored in a dynamically allocated memory. While
reloading the driver, this memory is freed and then allocated again. A
use-after-free might happen if during this time frame someone tries to
retrieve its value.

Since commit 070c63f20f6c ("net: devlink: allow to change namespaces
during reload") the use-after-free can be reliably triggered when
reloading the driver into a namespace, as after freeing the memory (via
reload_down() callback) all the parameters are notified.

Fix this by unpublishing and then re-publishing the parameters during
reload.

Fixes: 98bbf70c1c41 ("mlxsw: spectrum: add "acl_region_rehash_interval" devlink param")
Fixes: 7c62cfb8c574 ("devlink: publish params only after driver init is done")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index 14dcc78..4421ab2 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -1186,7 +1186,7 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
        if (err)
                goto err_thermal_init;
 
-       if (mlxsw_driver->params_register && !reload)
+       if (mlxsw_driver->params_register)
                devlink_params_publish(devlink);
 
        return 0;
@@ -1259,7 +1259,7 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
                        return;
        }
 
-       if (mlxsw_core->driver->params_unregister && !reload)
+       if (mlxsw_core->driver->params_unregister)
                devlink_params_unpublish(devlink);
        mlxsw_thermal_fini(mlxsw_core->thermal);
        mlxsw_hwmon_fini(mlxsw_core->hwmon);