From b20b8aec6ffc07bb547966b356780cd344f20f5b Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Wed, 15 Feb 2023 09:31:39 +0200 Subject: [PATCH] devlink: Fix netdev notifier chain corruption Cited commit changed devlink to register its netdev notifier block on the global netdev notifier chain instead of on the per network namespace one. However, when changing the network namespace of the devlink instance, devlink still tries to unregister its notifier block from the chain of the old namespace and register it on the chain of the new namespace. This results in corruption of the notifier chains, as the same notifier block is registered on two different chains: The global one and the per network namespace one. In turn, this causes other problems such as the inability to dismantle namespaces due to netdev reference count issues. Fix by preventing devlink from moving its notifier block between namespaces. Reproducer: # echo "10 1" > /sys/bus/netdevsim/new_device # ip netns add test123 # devlink dev reload netdevsim/netdevsim10 netns test123 # ip netns del test123 [ 71.935619] unregister_netdevice: waiting for lo to become free. Usage count = 2 [ 71.938348] leaked reference. Fixes: 565b4824c39f ("devlink: change port event netdev notifier from per-net to global") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Reviewed-by: Jacob Keller Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/r/20230215073139.1360108-1-idosch@nvidia.com Signed-off-by: Paolo Abeni --- include/linux/netdevice.h | 2 -- net/core/dev.c | 8 -------- net/core/devlink.c | 5 +---- 3 files changed, 1 insertion(+), 14 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index aad12a179e54..e6e02184c25a 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2839,8 +2839,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb); int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb); int unregister_netdevice_notifier_net(struct net *net, struct notifier_block *nb); -void move_netdevice_notifier_net(struct net *src_net, struct net *dst_net, - struct notifier_block *nb); int register_netdevice_notifier_dev_net(struct net_device *dev, struct notifier_block *nb, struct netdev_net_notifier *nn); diff --git a/net/core/dev.c b/net/core/dev.c index ea0a7bac1e5c..f23e287602b7 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1869,14 +1869,6 @@ static void __move_netdevice_notifier_net(struct net *src_net, __register_netdevice_notifier_net(dst_net, nb, true); } -void move_netdevice_notifier_net(struct net *src_net, struct net *dst_net, - struct notifier_block *nb) -{ - rtnl_lock(); - __move_netdevice_notifier_net(src_net, dst_net, nb); - rtnl_unlock(); -} - int register_netdevice_notifier_dev_net(struct net_device *dev, struct notifier_block *nb, struct netdev_net_notifier *nn) diff --git a/net/core/devlink.c b/net/core/devlink.c index 909a10e4b0dd..0bfc144df8b9 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4742,11 +4742,8 @@ static int devlink_reload(struct devlink *devlink, struct net *dest_net, if (err) return err; - if (dest_net && !net_eq(dest_net, curr_net)) { - move_netdevice_notifier_net(curr_net, dest_net, - &devlink->netdevice_nb); + if (dest_net && !net_eq(dest_net, curr_net)) write_pnet(&devlink->_net, dest_net); - } err = devlink->ops->reload_up(devlink, action, limit, actions_performed, extack); devlink_reload_failed_set(devlink, !!err);