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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: 565b4824c3 ("devlink: change port event netdev notifier from per-net to global")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230215073139.1360108-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Ido Schimmel 2023-02-15 09:31:39 +02:00 committed by Paolo Abeni
parent 5d54cb1767
commit b20b8aec6f
3 changed files with 1 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/netdevice.h
View File

@ -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);

8
net/core/dev.c
View File

@ -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)

5
net/core/devlink.c
View File

@ -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);