From: Roi Dayan roid@nvidia.com
commit 880b517691908fb753019b9b27cd082e7617debd upstream.
When changing mode to switchdev, rep bridge init registered to netdevice notifier holds the devlink lock and then takes pernet_ops_rwsem. At that time deleting a netns holds pernet_ops_rwsem and then takes the devlink lock.
Example sequence is: $ ip netns add foo $ devlink dev eswitch set pci/0000:00:08.0 mode switchdev & $ ip netns del foo
deleting netns trace:
[ 1185.365555] ? devlink_pernet_pre_exit+0x74/0x1c0 [ 1185.368331] ? mutex_lock_io_nested+0x13f0/0x13f0 [ 1185.370984] ? xt_find_table+0x40/0x100 [ 1185.373244] ? __mutex_lock+0x24a/0x15a0 [ 1185.375494] ? net_generic+0xa0/0x1c0 [ 1185.376844] ? wait_for_completion_io+0x280/0x280 [ 1185.377767] ? devlink_pernet_pre_exit+0x74/0x1c0 [ 1185.378686] devlink_pernet_pre_exit+0x74/0x1c0 [ 1185.379579] ? devlink_nl_cmd_get_dumpit+0x3a0/0x3a0 [ 1185.380557] ? xt_find_table+0xda/0x100 [ 1185.381367] cleanup_net+0x372/0x8e0
changing mode to switchdev trace:
[ 1185.411267] down_write+0x13a/0x150 [ 1185.412029] ? down_write_killable+0x180/0x180 [ 1185.413005] register_netdevice_notifier+0x1e/0x210 [ 1185.414000] mlx5e_rep_bridge_init+0x181/0x360 [mlx5_core] [ 1185.415243] mlx5e_uplink_rep_enable+0x269/0x480 [mlx5_core] [ 1185.416464] ? mlx5e_uplink_rep_disable+0x210/0x210 [mlx5_core] [ 1185.417749] mlx5e_attach_netdev+0x232/0x400 [mlx5_core] [ 1185.418906] mlx5e_netdev_attach_profile+0x15b/0x1e0 [mlx5_core] [ 1185.420172] mlx5e_netdev_change_profile+0x15a/0x1d0 [mlx5_core] [ 1185.421459] mlx5e_vport_rep_load+0x557/0x780 [mlx5_core] [ 1185.422624] ? mlx5e_stats_grp_vport_rep_num_stats+0x10/0x10 [mlx5_core] [ 1185.424006] mlx5_esw_offloads_rep_load+0xdb/0x190 [mlx5_core] [ 1185.425277] esw_offloads_enable+0xd74/0x14a0 [mlx5_core]
Fix this by registering rep bridges for per net netdev notifier instead of global one, which operats on the net namespace without holding the pernet_ops_rwsem.
Fixes: 19e9bfa044f3 ("net/mlx5: Bridge, add offload infrastructure") Signed-off-by: Roi Dayan roid@nvidia.com Reviewed-by: Vlad Buslov vladbu@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c @@ -491,7 +491,7 @@ void mlx5e_rep_bridge_init(struct mlx5e_ }
br_offloads->netdev_nb.notifier_call = mlx5_esw_bridge_switchdev_port_event; - err = register_netdevice_notifier(&br_offloads->netdev_nb); + err = register_netdevice_notifier_net(&init_net, &br_offloads->netdev_nb); if (err) { esw_warn(mdev, "Failed to register bridge offloads netdevice notifier (err=%d)\n", err); @@ -526,7 +526,7 @@ void mlx5e_rep_bridge_cleanup(struct mlx return;
cancel_delayed_work_sync(&br_offloads->update_work); - unregister_netdevice_notifier(&br_offloads->netdev_nb); + unregister_netdevice_notifier_net(&init_net, &br_offloads->netdev_nb); unregister_switchdev_blocking_notifier(&br_offloads->nb_blk); unregister_switchdev_notifier(&br_offloads->nb); destroy_workqueue(br_offloads->wq);