From: Jouni Hogander <jouni.hogander@unikie.com>
Date: Thu, 5 Dec 2019 13:57:07 +0000 (+0200)
Subject: net-sysfs: Call dev_hold always in netdev_queue_add_kobject
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=e0b60903b434a7ee21ba8d8659f207ed84101e89;p=openwrt%2Fstaging%2Fblogic.git

net-sysfs: Call dev_hold always in netdev_queue_add_kobject

Dev_hold has to be called always in netdev_queue_add_kobject.
Otherwise usage count drops below 0 in case of failure in
kobject_init_and_add.

Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
Reported-by: Hulk Robot <hulkci@huawei.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Miller <davem@davemloft.net>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ae3bcb1540ec..5c4624298996 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1459,14 +1459,17 @@ static int netdev_queue_add_kobject(struct net_device *dev, int index)
 	struct kobject *kobj = &queue->kobj;
 	int error = 0;
 
+	/* Kobject_put later will trigger netdev_queue_release call
+	 * which decreases dev refcount: Take that reference here
+	 */
+	dev_hold(queue->dev);
+
 	kobj->kset = dev->queues_kset;
 	error = kobject_init_and_add(kobj, &netdev_queue_ktype, NULL,
 				     "tx-%u", index);
 	if (error)
 		goto err;
 
-	dev_hold(queue->dev);
-
 #ifdef CONFIG_BQL
 	error = sysfs_create_group(kobj, &dql_group);
 	if (error)