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devlink: disallow reload operation during device cleanup

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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: Ido Schimmel <idosch@mellanox.com>
Fixes: 2d8dc5bbf4 ("devlink: Add support for reload")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Pirko 2019-11-09 11:29:46 +01:00 committed by David S. Miller
parent 0058b0a506
commit 5a508a254b
5 changed files with 52 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/net/ethernet/mellanox/mlx4/main.c
View File

@ -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;

6
drivers/net/ethernet/mellanox/mlxsw/core.c
View File

@ -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

2
drivers/net/netdevsim/dev.c
View File

@ -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);

5
include/net/devlink.h
View File

@ -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,

39
net/core/devlink.c
View File

@ -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
*