tuntap: attach queue 0 before registering netdevice (eb0fb363) · Commits · 戴 / test

We attach queue 0 after registering netdevice currently. This leads to call netif_set_real_num_{tx|rx}_queues() after registering the netdevice. Since we allow tun/tap has a maximum of 1024 queues, this may lead a huge number of uevents to be injected to userspace since we create 2048 kobjects and then remove 2046. Solve this problem by attaching queue 0 and set the real number of queues before registering netdevice. Reported-by:

Jiri Slaby <jslaby@suse.cz> Tested-by:

Jiri Slaby <jslaby@suse.cz> Signed-off-by:

Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/tun.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -493,9 +493,6 @@ static int tun_attach(struct tun_struct tun, struct file file)

		tun_set_real_num_queues(tun);

		if (tun->numqueues == 1)
		netif_carrier_on(tun->dev);

		/* device is allowed to go away first, so no need to hold extra
		* refcnt.
		*/
		@@ -1612,6 +1609,10 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)
		TUN_USER_FEATURES;
		dev->features = dev->hw_features;

		err = tun_attach(tun, file);
		if (err < 0)
		goto err_free_dev;

		err = register_netdevice(tun->dev);
		if (err < 0)
		goto err_free_dev;
		@@ -1621,9 +1622,7 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)
		device_create_file(&tun->dev->dev, &dev_attr_group))
		pr_err("Failed to create tun sysfs files\n");

		err = tun_attach(tun, file);
		if (err < 0)
		goto err_free_dev;
		netif_carrier_on(tun->dev);
		}

		tun_debug(KERN_INFO, tun, "tun_set_iff\n");

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