net-sysfs: call dev_hold if kobject_init_and_add success

commit a3e23f719f5c4a38ffb3d30c8d7632a4ed8ccd9e upstream.

In netdev_queue_add_kobject and rx_queue_add_kobject,
if sysfs_create_group failed, kobject_put will call
netdev_queue_release to decrease dev refcont, however
dev_hold has not be called. So we will see this while
unregistering dev:

unregister_netdevice: waiting for bcsh0 to become free. Usage count = -1

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: d0d668371679 ("net: don't decrement kobj reference count on init failure")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index cd332d0fa930c68500995a783baf4ce4636e62fc..7550d098e3b7fb53b9e3f0a818a373d0e457b040 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -788,6 +788,8 @@ static int rx_queue_add_kobject(struct net_device *net, int index)
        if (error)
                return error;
 
+       dev_hold(queue->dev);
+
        if (net->sysfs_rx_queue_group) {
                error = sysfs_create_group(kobj, net->sysfs_rx_queue_group);
                if (error) {
@@ -797,7 +799,6 @@ static int rx_queue_add_kobject(struct net_device *net, int index)
        }
 
        kobject_uevent(kobj, KOBJ_ADD);
-       dev_hold(queue->dev);
 
        return error;
 }
@@ -1146,6 +1147,8 @@ static int netdev_queue_add_kobject(struct net_device *net, int index)
        if (error)
                return error;
 
+       dev_hold(queue->dev);
+
 #ifdef CONFIG_BQL
        error = sysfs_create_group(kobj, &dql_group);
        if (error) {
@@ -1155,7 +1158,6 @@ static int netdev_queue_add_kobject(struct net_device *net, int index)
 #endif
 
        kobject_uevent(kobj, KOBJ_ADD);
-       dev_hold(queue->dev);
 
        return 0;
 }