kernel: fix refcnt leak in LED netdev trigger on interface rename
Renaming a netdev-trigger-tracked interface was resulting in an
unbalanced dev_hold().
Example:
> iw phy phy0 interface add foo type __ap
> echo netdev > trigger
> echo foo > device_name
> ip link set foo name bar
> iw dev bar del
[ 237.355366] unregister_netdevice: waiting for bar to become free. Usage count = 1
[ 247.435362] unregister_netdevice: waiting for bar to become free. Usage count = 1
[ 257.545366] unregister_netdevice: waiting for bar to become free. Usage count = 1
Above problem was caused by trigger checking a dev->name which obviously
changes after renaming an interface. It meant missing all further events
including the NETDEV_UNREGISTER which is required for calling dev_put().
This change fixes that by:
1) Comparing device struct *address* for notification-filtering purposes
2) Dropping unneeded NETDEV_CHANGENAME code (no behavior change)
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit eea538204b
)
This commit is contained in:
parent
eab6537449
commit
981f5f7e40
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@ -264,39 +264,35 @@ static int netdev_trig_notify(struct notifier_block *nb,
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struct net_device *dev = netdev_notifier_info_to_dev((struct netdev_notifier_info *) dv);
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struct led_netdev_data *trigger_data = container_of(nb, struct led_netdev_data, notifier);
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if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER && evt != NETDEV_CHANGENAME)
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if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER)
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return NOTIFY_DONE;
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if (strcmp(dev->name, trigger_data->device_name))
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if (!(dev == trigger_data->net_dev ||
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(evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
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return NOTIFY_DONE;
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cancel_delayed_work_sync(&trigger_data->work);
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spin_lock_bh(&trigger_data->lock);
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if (evt == NETDEV_REGISTER || evt == NETDEV_CHANGENAME) {
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if (trigger_data->net_dev != NULL)
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dev_put(trigger_data->net_dev);
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switch (evt) {
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case NETDEV_REGISTER:
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dev_hold(dev);
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trigger_data->net_dev = dev;
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trigger_data->link_up = 0;
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goto done;
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}
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if (evt == NETDEV_UNREGISTER && trigger_data->net_dev != NULL) {
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break;
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case NETDEV_UNREGISTER:
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dev_put(trigger_data->net_dev);
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trigger_data->net_dev = NULL;
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goto done;
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break;
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default: /* UP / DOWN / CHANGE */
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trigger_data->link_up = (evt != NETDEV_DOWN && netif_carrier_ok(dev));
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set_baseline_state(trigger_data);
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break;
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}
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/* UP / DOWN / CHANGE */
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trigger_data->link_up = (evt != NETDEV_DOWN && netif_carrier_ok(dev));
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set_baseline_state(trigger_data);
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done:
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spin_unlock_bh(&trigger_data->lock);
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return NOTIFY_DONE;
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}
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