From: Jiri Pirko <jiri@mellanox.com>
Date: Sat, 9 Nov 2019 11:29:46 +0100
Subject: devlink: disallow reload operation during device cleanup
Git-commit: 5a508a254bed9a2e36a5fb96c9065532a6bf1e9c
Patch-mainline: 5.4-rc8
References: bnc#1151927 5.3.12
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: 2d8dc5bbf4e7 ("devlink: Add support for reload")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/net/ethernet/mellanox/mlx4/main.c | 3 ++
drivers/net/ethernet/mellanox/mlxsw/core.c | 6 +++-
drivers/net/netdevsim/dev.c | 2 +
include/net/devlink.h | 5 ++-
net/core/devlink.c | 39 ++++++++++++++++++++++++++++-
5 files changed, 52 insertions(+), 3 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -4011,6 +4011,7 @@ static int mlx4_init_one(struct pci_dev
goto err_params_unregister;
devlink_params_publish(devlink);
+ devlink_reload_enable(devlink);
pci_save_state(pdev);
return 0;
@@ -4122,6 +4123,8 @@ static void mlx4_remove_one(struct pci_d
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;
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -1186,8 +1186,10 @@ __mlxsw_core_bus_device_register(const s
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(st
{
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
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -708,6 +708,7 @@ nsim_dev_create(struct nsim_bus_dev *nsi
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
{
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);
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -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,
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -2699,7 +2699,7 @@ static int devlink_nl_cmd_reload(struct
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);
@@ -6196,6 +6196,8 @@ 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);
@@ -6203,6 +6205,41 @@ void devlink_unregister(struct devlink *
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
*
* @devlink: devlink