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Commit 5a508a25 authored by Jiri Pirko's avatar Jiri Pirko Committed by David S. Miller
Browse files

devlink: disallow reload operation during device cleanup 



There is a race between driver code that does setup/cleanup of device
and devlink reload operation that in some drivers works with the same
code. Use after free could we easily obtained by running:

while true; do
        echo "0000:00:10.0" >/sys/bus/pci/drivers/mlxsw_spectrum2/bind
        devlink dev reload pci/0000:00:10.0 &
        echo "0000:00:10.0" >/sys/bus/pci/drivers/mlxsw_spectrum2/unbind
done

Fix this by enabling reload only after setup of device is complete and
disabling it at the beginning of the cleanup process.

Reported-by: default avatarIdo Schimmel <idosch@mellanox.com>
Fixes: 2d8dc5bb ("devlink: Add support for reload")
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0058b0a5

drivers/net/ethernet/mellanox/mlx4/main.c

+3 −0
Original line number Diff line number Diff line
@@ -4010,6 +4010,7 @@ static int mlx4_init_one(struct pci_dev *pdev, const struct pci_device_id *id) 
		goto err_params_unregister;



	devlink_params_publish(devlink);

	devlink_reload_enable(devlink);

	pci_save_state(pdev);

	return 0;
@@ -4121,6 +4122,8 @@ static void mlx4_remove_one(struct pci_dev *pdev) 
	struct devlink *devlink = priv_to_devlink(priv);

	int active_vfs = 0;



	devlink_reload_disable(devlink);



	if (mlx4_is_slave(dev))

		persist->interface_state |= MLX4_INTERFACE_STATE_NOWAIT;

drivers/net/ethernet/mellanox/mlxsw/core.c

+5 −1
Original line number Diff line number Diff line
@@ -1186,8 +1186,10 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info, 
	if (err)

		goto err_thermal_init;



	if (mlxsw_driver->params_register)

	if (mlxsw_driver->params_register) {

		devlink_params_publish(devlink);

		devlink_reload_enable(devlink);

	}



	return 0;
@@ -1249,6 +1251,8 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core, 
{

	struct devlink *devlink = priv_to_devlink(mlxsw_core);



	if (!reload)

		devlink_reload_disable(devlink);

	if (devlink_is_reload_failed(devlink)) {

		if (!reload)

			/* Only the parts that were not de-initialized in the

drivers/net/netdevsim/dev.c

+2 −0
Original line number Diff line number Diff line
@@ -708,6 +708,7 @@ nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev, unsigned int port_count) 
		goto err_debugfs_exit;



	devlink_params_publish(devlink);

	devlink_reload_enable(devlink);

	return nsim_dev;



err_debugfs_exit:
@@ -732,6 +733,7 @@ static void nsim_dev_destroy(struct nsim_dev *nsim_dev) 
{

	struct devlink *devlink = priv_to_devlink(nsim_dev);



	devlink_reload_disable(devlink);

	nsim_bpf_dev_exit(nsim_dev);

	nsim_dev_debugfs_exit(nsim_dev);

	nsim_dev_traps_exit(devlink);

include/net/devlink.h

+4 −1
Original line number Diff line number Diff line
@@ -38,7 +38,8 @@ struct devlink { 
	struct device *dev;

	possible_net_t _net;

	struct mutex lock;

	bool reload_failed;

	u8 reload_failed:1,

	   reload_enabled:1;

	char priv[0] __aligned(NETDEV_ALIGN);

};
@@ -774,6 +775,8 @@ struct ib_device; 
struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size);

int devlink_register(struct devlink *devlink, struct device *dev);

void devlink_unregister(struct devlink *devlink);

void devlink_reload_enable(struct devlink *devlink);

void devlink_reload_disable(struct devlink *devlink);

void devlink_free(struct devlink *devlink);

int devlink_port_register(struct devlink *devlink,

			  struct devlink_port *devlink_port,

net/core/devlink.c

+38 −1
Original line number Diff line number Diff line
@@ -2699,7 +2699,7 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info) 
	struct devlink *devlink = info->user_ptr[0];

	int err;



	if (!devlink_reload_supported(devlink))

	if (!devlink_reload_supported(devlink) || !devlink->reload_enabled)

		return -EOPNOTSUPP;



	err = devlink_resources_validate(devlink, NULL, info);
@@ -6196,12 +6196,49 @@ EXPORT_SYMBOL_GPL(devlink_register); 
void devlink_unregister(struct devlink *devlink)

{

	mutex_lock(&devlink_mutex);

	WARN_ON(devlink_reload_supported(devlink) &&

		devlink->reload_enabled);

	devlink_notify(devlink, DEVLINK_CMD_DEL);

	list_del(&devlink->list);

	mutex_unlock(&devlink_mutex);

}

EXPORT_SYMBOL_GPL(devlink_unregister);



/**

 *	devlink_reload_enable - Enable reload of devlink instance

 *

 *	@devlink: devlink

 *

 *	Should be called at end of device initialization

 *	process when reload operation is supported.

 */

void devlink_reload_enable(struct devlink *devlink)

{

	mutex_lock(&devlink_mutex);

	devlink->reload_enabled = true;

	mutex_unlock(&devlink_mutex);

}

EXPORT_SYMBOL_GPL(devlink_reload_enable);



/**

 *	devlink_reload_disable - Disable reload of devlink instance

 *

 *	@devlink: devlink

 *

 *	Should be called at the beginning of device cleanup

 *	process when reload operation is supported.

 */

void devlink_reload_disable(struct devlink *devlink)

{

	mutex_lock(&devlink_mutex);

	/* Mutex is taken which ensures that no reload operation is in

	 * progress while setting up forbidded flag.

	 */

	devlink->reload_enabled = false;

	mutex_unlock(&devlink_mutex);

}

EXPORT_SYMBOL_GPL(devlink_reload_disable);



/**

 *	devlink_free - Free devlink instance resources

 *