From dd7590a3ab3f0804ed5e930295e2caa5979e3958 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Date: Thu, 28 Feb 2019 22:57:33 +0100 Subject: [PATCH] leds: trigger: netdev: fix refcnt leak on interface rename MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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) Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger") Signed-off-by: Rafał Miłecki Acked-by: Pavel Machek Signed-off-by: Jacek Anaszewski --- drivers/leds/trigger/ledtrig-netdev.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/drivers/leds/trigger/ledtrig-netdev.c +++ b/drivers/leds/trigger/ledtrig-netdev.c @@ -299,11 +299,11 @@ static int netdev_trig_notify(struct not notifier); if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE - && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER - && evt != NETDEV_CHANGENAME) + && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER) return NOTIFY_DONE; - if (strcmp(dev->name, trigger_data->device_name)) + if (!(dev == trigger_data->net_dev || + (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name)))) return NOTIFY_DONE; cancel_delayed_work_sync(&trigger_data->work); @@ -318,12 +318,9 @@ static int netdev_trig_notify(struct not dev_hold(dev); trigger_data->net_dev = dev; break; - case NETDEV_CHANGENAME: case NETDEV_UNREGISTER: - if (trigger_data->net_dev) { - dev_put(trigger_data->net_dev); - trigger_data->net_dev = NULL; - } + dev_put(trigger_data->net_dev); + trigger_data->net_dev = NULL; break; case NETDEV_UP: case NETDEV_CHANGE: