net: Fix inconsistent teardown and release of private netdev state.

Network devices can allocate reasources and private memory using netdev_ops->ndo_init(). However, the release of these resources can occur in one of two different places. Either netdev_ops->ndo_uninit() or netdev->destructor(). The decision of which operation frees the resources depends upon whether it is necessary for all netdev refs to be released before it is safe to perform the freeing. netdev_ops->ndo_uninit() presumably can occur right after the NETDEV_UNREGISTER notifier completes and the unicast and multicast address lists are flushed. netdev->destructor(), on the other hand, does not run until the netdev references all go away. Further complicating the situation is that netdev->destructor() almost universally does also a free_netdev(). This creates a problem for the logic in register_netdevice(). Because all callers of register_netdevice() manage the freeing of the netdev, and invoke free_netdev(dev) if register_netdevice() fails. If netdev_ops->ndo_init() succeeds, but something else fails inside of register_netdevice(), it does call ndo_ops->ndo_uninit(). But it is not able to invoke netdev->destructor(). This is because netdev->destructor() will do a free_netdev() and then the caller of register_netdevice() will do the same. However, this means that the resources that would normally be released by netdev->destructor() will not be. Over the years drivers have added local hacks to deal with this, by invoking their destructor parts by hand when register_netdevice() fails. Many drivers do not try to deal with this, and instead we have leaks. Let's close this hole by formalizing the distinction between what private things need to be freed up by netdev->destructor() and whether the driver needs unregister_netdevice() to perform the free_netdev(). netdev->priv_destructor() performs all actions to free up the private resources that used to be freed by netdev->destructor(), except for free_netdev(). netdev->needs_free_netdev is a boolean that indicates whether free_netdev() should be done at the end of unregister_netdevice(). Now, register_netdevice() can sanely release all resources after ndo_ops->ndo_init() succeeds, by invoking both ndo_ops->ndo_uninit() and netdev->priv_destructor(). And at the end of unregister_netdevice(), we invoke netdev->priv_destructor() and optionally call free_netdev(). Signed-off-by: David S. Miller <davem@davemloft.net>
torvalds · Jun 7, 2017 · cf124db · cf124db
1 parent 7005cad
commit cf124db
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Showing 62 changed files with 105 additions and 103 deletions.
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
@@ -4192,7 +4192,6 @@ static void bond_destructor(struct net_device *bond_dev)
 	struct bonding *bond = netdev_priv(bond_dev);
 	if (bond->wq)
 		destroy_workqueue(bond->wq);
-	free_netdev(bond_dev);
 }
 
 void bond_setup(struct net_device *bond_dev)
@@ -4212,7 +4211,8 @@ void bond_setup(struct net_device *bond_dev)
 	bond_dev->netdev_ops = &bond_netdev_ops;
 	bond_dev->ethtool_ops = &bond_ethtool_ops;
 
-	bond_dev->destructor = bond_destructor;
+	bond_dev->needs_free_netdev = true;
+	bond_dev->priv_destructor = bond_destructor;
 
 	SET_NETDEV_DEVTYPE(bond_dev, &bond_type);
 
@@ -4736,7 +4736,7 @@ int bond_create(struct net *net, const char *name)
 
 	rtnl_unlock();
 	if (res < 0)
-		bond_destructor(bond_dev);
+		free_netdev(bond_dev);
 	return res;
 }
 

diff --git a/drivers/net/caif/caif_hsi.c b/drivers/net/caif/caif_hsi.c
@@ -1121,7 +1121,7 @@ static void cfhsi_setup(struct net_device *dev)
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 	dev->mtu = CFHSI_MAX_CAIF_FRAME_SZ;
 	dev->priv_flags |= IFF_NO_QUEUE;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	dev->netdev_ops = &cfhsi_netdevops;
 	for (i = 0; i < CFHSI_PRIO_LAST; ++i)
 		skb_queue_head_init(&cfhsi->qhead[i]);

diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c
@@ -428,7 +428,7 @@ static void caifdev_setup(struct net_device *dev)
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 	dev->mtu = CAIF_MAX_MTU;
 	dev->priv_flags |= IFF_NO_QUEUE;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	skb_queue_head_init(&serdev->head);
 	serdev->common.link_select = CAIF_LINK_LOW_LATENCY;
 	serdev->common.use_frag = true;

diff --git a/drivers/net/caif/caif_spi.c b/drivers/net/caif/caif_spi.c
@@ -712,7 +712,7 @@ static void cfspi_setup(struct net_device *dev)
 	dev->flags = IFF_NOARP | IFF_POINTOPOINT;
 	dev->priv_flags |= IFF_NO_QUEUE;
 	dev->mtu = SPI_MAX_PAYLOAD_SIZE;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	skb_queue_head_init(&cfspi->qhead);
 	skb_queue_head_init(&cfspi->chead);
 	cfspi->cfdev.link_select = CAIF_LINK_HIGH_BANDW;

diff --git a/drivers/net/caif/caif_virtio.c b/drivers/net/caif/caif_virtio.c
@@ -617,7 +617,7 @@ static void cfv_netdev_setup(struct net_device *netdev)
 	netdev->tx_queue_len = 100;
 	netdev->flags = IFF_POINTOPOINT | IFF_NOARP;
 	netdev->mtu = CFV_DEF_MTU_SIZE;
-	netdev->destructor = free_netdev;
+	netdev->needs_free_netdev = true;
 }
 
 /* Create debugfs counters for the device */

diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
@@ -417,7 +417,7 @@ static int slc_open(struct net_device *dev)
 static void slc_free_netdev(struct net_device *dev)
 {
 	int i = dev->base_addr;
-	free_netdev(dev);
+
 	slcan_devs[i] = NULL;
 }
 
@@ -436,7 +436,8 @@ static const struct net_device_ops slc_netdev_ops = {
 static void slc_setup(struct net_device *dev)
 {
 	dev->netdev_ops		= &slc_netdev_ops;
-	dev->destructor		= slc_free_netdev;
+	dev->needs_free_netdev	= true;
+	dev->priv_destructor	= slc_free_netdev;
 
 	dev->hard_header_len	= 0;
 	dev->addr_len		= 0;
@@ -761,8 +762,6 @@ static void __exit slcan_exit(void)
 		if (sl->tty) {
 			printk(KERN_ERR "%s: tty discipline still running\n",
 			       dev->name);
-			/* Intentionally leak the control block. */
-			dev->destructor = NULL;
 		}
 
 		unregister_netdev(dev);

diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
@@ -163,7 +163,7 @@ static void vcan_setup(struct net_device *dev)
 		dev->flags |= IFF_ECHO;
 
 	dev->netdev_ops		= &vcan_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 }
 
 static struct rtnl_link_ops vcan_link_ops __read_mostly = {

diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c
@@ -156,7 +156,7 @@ static void vxcan_setup(struct net_device *dev)
 	dev->tx_queue_len	= 0;
 	dev->flags		= (IFF_NOARP|IFF_ECHO);
 	dev->netdev_ops		= &vxcan_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 }
 
 /* forward declaration for rtnl_create_link() */

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
@@ -328,7 +328,6 @@ static void dummy_free_netdev(struct net_device *dev)
 	struct dummy_priv *priv = netdev_priv(dev);
 
 	kfree(priv->vfinfo);
-	free_netdev(dev);
 }
 
 static void dummy_setup(struct net_device *dev)
@@ -338,7 +337,8 @@ static void dummy_setup(struct net_device *dev)
 	/* Initialize the device structure. */
 	dev->netdev_ops = &dummy_netdev_ops;
 	dev->ethtool_ops = &dummy_ethtool_ops;
-	dev->destructor = dummy_free_netdev;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = dummy_free_netdev;
 
 	/* Fill in device structure with ethernet-generic values. */
 	dev->flags |= IFF_NOARP;

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -4525,7 +4525,7 @@ static void dummy_setup(struct net_device *dev)
 	/* Initialize the device structure. */
 	dev->netdev_ops = &cxgb4_mgmt_netdev_ops;
 	dev->ethtool_ops = &cxgb4_mgmt_ethtool_ops;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 }
 
 static int config_mgmt_dev(struct pci_dev *pdev)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
@@ -1007,7 +1007,7 @@ static void geneve_setup(struct net_device *dev)
 
 	dev->netdev_ops = &geneve_netdev_ops;
 	dev->ethtool_ops = &geneve_ethtool_ops;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 
 	SET_NETDEV_DEVTYPE(dev, &geneve_type);
 

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
@@ -611,7 +611,7 @@ static const struct net_device_ops gtp_netdev_ops = {
 static void gtp_link_setup(struct net_device *dev)
 {
 	dev->netdev_ops		= &gtp_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 
 	dev->hard_header_len = 0;
 	dev->addr_len = 0;

diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
@@ -311,7 +311,7 @@ static void sp_setup(struct net_device *dev)
 {
 	/* Finish setting up the DEVICE info. */
 	dev->netdev_ops		= &sp_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 	dev->mtu		= SIXP_MTU;
 	dev->hard_header_len	= AX25_MAX_HEADER_LEN;
 	dev->header_ops 	= &ax25_header_ops;

diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c
@@ -476,7 +476,7 @@ static const struct net_device_ops bpq_netdev_ops = {
 static void bpq_setup(struct net_device *dev)
 {
 	dev->netdev_ops	     = &bpq_netdev_ops;
-	dev->destructor	     = free_netdev;
+	dev->needs_free_netdev = true;
 
 	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 	memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
@@ -207,7 +207,6 @@ static void ifb_dev_free(struct net_device *dev)
 		__skb_queue_purge(&txp->tq);
 	}
 	kfree(dp->tx_private);
-	free_netdev(dev);
 }
 
 static void ifb_setup(struct net_device *dev)
@@ -230,7 +229,8 @@ static void ifb_setup(struct net_device *dev)
 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 	netif_keep_dst(dev);
 	eth_hw_addr_random(dev);
-	dev->destructor = ifb_dev_free;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = ifb_dev_free;
 }
 
 static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
@@ -632,7 +632,7 @@ void ipvlan_link_setup(struct net_device *dev)
 	dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
 	dev->priv_flags |= IFF_UNICAST_FLT | IFF_NO_QUEUE;
 	dev->netdev_ops = &ipvlan_netdev_ops;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	dev->header_ops = &ipvlan_header_ops;
 	dev->ethtool_ops = &ipvlan_ethtool_ops;
 }

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
@@ -159,7 +159,6 @@ static void loopback_dev_free(struct net_device *dev)
 {
 	dev_net(dev)->loopback_dev = NULL;
 	free_percpu(dev->lstats);
-	free_netdev(dev);
 }
 
 static const struct net_device_ops loopback_ops = {
@@ -196,7 +195,8 @@ static void loopback_setup(struct net_device *dev)
 	dev->ethtool_ops	= &loopback_ethtool_ops;
 	dev->header_ops		= &eth_header_ops;
 	dev->netdev_ops		= &loopback_ops;
-	dev->destructor		= loopback_dev_free;
+	dev->needs_free_netdev	= true;
+	dev->priv_destructor	= loopback_dev_free;
 }
 
 /* Setup and register the loopback device. */

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
@@ -2996,7 +2996,6 @@ static void macsec_free_netdev(struct net_device *dev)
 	free_percpu(macsec->secy.tx_sc.stats);
 
 	dev_put(real_dev);
-	free_netdev(dev);
 }
 
 static void macsec_setup(struct net_device *dev)
@@ -3006,7 +3005,8 @@ static void macsec_setup(struct net_device *dev)
 	dev->max_mtu = ETH_MAX_MTU;
 	dev->priv_flags |= IFF_NO_QUEUE;
 	dev->netdev_ops = &macsec_netdev_ops;
-	dev->destructor = macsec_free_netdev;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = macsec_free_netdev;
 	SET_NETDEV_DEVTYPE(dev, &macsec_type);
 
 	eth_zero_addr(dev->broadcast);

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
@@ -1092,7 +1092,7 @@ void macvlan_common_setup(struct net_device *dev)
 	netif_keep_dst(dev);
 	dev->priv_flags	       |= IFF_UNICAST_FLT;
 	dev->netdev_ops		= &macvlan_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 	dev->header_ops		= &macvlan_hard_header_ops;
 	dev->ethtool_ops	= &macvlan_ethtool_ops;
 }

diff --git a/drivers/net/nlmon.c b/drivers/net/nlmon.c
@@ -113,7 +113,7 @@ static void nlmon_setup(struct net_device *dev)
 
 	dev->netdev_ops	= &nlmon_ops;
 	dev->ethtool_ops = &nlmon_ethtool_ops;
-	dev->destructor	= free_netdev;
+	dev->needs_free_netdev = true;
 
 	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 			NETIF_F_HIGHDMA | NETIF_F_LLTX;

diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
@@ -629,7 +629,7 @@ static void sl_uninit(struct net_device *dev)
 static void sl_free_netdev(struct net_device *dev)
 {
 	int i = dev->base_addr;
-	free_netdev(dev);
+
 	slip_devs[i] = NULL;
 }
 
@@ -651,7 +651,8 @@ static const struct net_device_ops sl_netdev_ops = {
 static void sl_setup(struct net_device *dev)
 {
 	dev->netdev_ops		= &sl_netdev_ops;
-	dev->destructor		= sl_free_netdev;
+	dev->needs_free_netdev	= true;
+	dev->priv_destructor	= sl_free_netdev;
 
 	dev->hard_header_len	= 0;
 	dev->addr_len		= 0;
@@ -1369,8 +1370,6 @@ static void __exit slip_exit(void)
 		if (sl->tty) {
 			printk(KERN_ERR "%s: tty discipline still running\n",
 			       dev->name);
-			/* Intentionally leak the control block. */
-			dev->destructor = NULL;
 		}
 
 		unregister_netdev(dev);

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
@@ -1643,7 +1643,6 @@ static void team_destructor(struct net_device *dev)
 	struct team *team = netdev_priv(dev);
 
 	free_percpu(team->pcpu_stats);
-	free_netdev(dev);
 }
 
 static int team_open(struct net_device *dev)
@@ -2079,7 +2078,8 @@ static void team_setup(struct net_device *dev)
 
 	dev->netdev_ops = &team_netdev_ops;
 	dev->ethtool_ops = &team_ethtool_ops;
-	dev->destructor	= team_destructor;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = team_destructor;
 	dev->priv_flags &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
 	dev->priv_flags |= IFF_NO_QUEUE;
 	dev->priv_flags |= IFF_TEAM;

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
@@ -1560,7 +1560,6 @@ static void tun_free_netdev(struct net_device *dev)
 	free_percpu(tun->pcpu_stats);
 	tun_flow_uninit(tun);
 	security_tun_dev_free_security(tun->security);
-	free_netdev(dev);
 }
 
 static void tun_setup(struct net_device *dev)
@@ -1571,7 +1570,8 @@ static void tun_setup(struct net_device *dev)
 	tun->group = INVALID_GID;
 
 	dev->ethtool_ops = &tun_ethtool_ops;
-	dev->destructor = tun_free_netdev;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = tun_free_netdev;
 	/* We prefer our own queue length */
 	dev->tx_queue_len = TUN_READQ_SIZE;
 }

diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c
@@ -298,7 +298,7 @@ static void usbpn_setup(struct net_device *dev)
 	dev->addr_len		= 1;
 	dev->tx_queue_len	= 3;
 
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 }
 
 /*

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
@@ -123,7 +123,7 @@ static void qmimux_setup(struct net_device *dev)
 	dev->addr_len        = 0;
 	dev->flags           = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 	dev->netdev_ops      = &qmimux_netdev_ops;
-	dev->destructor      = free_netdev;
+	dev->needs_free_netdev = true;
 }
 
 static struct net_device *qmimux_find_dev(struct usbnet *dev, u8 mux_id)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
@@ -222,7 +222,6 @@ static int veth_dev_init(struct net_device *dev)
 static void veth_dev_free(struct net_device *dev)
 {
 	free_percpu(dev->vstats);
-	free_netdev(dev);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -317,7 +316,8 @@ static void veth_setup(struct net_device *dev)
 			       NETIF_F_HW_VLAN_STAG_TX |
 			       NETIF_F_HW_VLAN_CTAG_RX |
 			       NETIF_F_HW_VLAN_STAG_RX);
-	dev->destructor = veth_dev_free;
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = veth_dev_free;
 	dev->max_mtu = ETH_MAX_MTU;
 
 	dev->hw_features = VETH_FEATURES;

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
@@ -1348,7 +1348,7 @@ static void vrf_setup(struct net_device *dev)
 	dev->netdev_ops = &vrf_netdev_ops;
 	dev->l3mdev_ops = &vrf_l3mdev_ops;
 	dev->ethtool_ops = &vrf_ethtool_ops;
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 
 	/* Fill in device structure with ethernet-generic values. */
 	eth_hw_addr_random(dev);

diff --git a/drivers/net/vsockmon.c b/drivers/net/vsockmon.c
@@ -135,7 +135,7 @@ static void vsockmon_setup(struct net_device *dev)
 
 	dev->netdev_ops	= &vsockmon_ops;
 	dev->ethtool_ops = &vsockmon_ethtool_ops;
-	dev->destructor	= free_netdev;
+	dev->needs_free_netdev = true;
 
 	dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
 			NETIF_F_HIGHDMA | NETIF_F_LLTX;

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
@@ -2611,7 +2611,7 @@ static void vxlan_setup(struct net_device *dev)
 	eth_hw_addr_random(dev);
 	ether_setup(dev);
 
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	SET_NETDEV_DEVTYPE(dev, &vxlan_type);
 
 	dev->features	|= NETIF_F_LLTX;

diff --git a/drivers/net/wan/dlci.c b/drivers/net/wan/dlci.c
@@ -475,7 +475,7 @@ static void dlci_setup(struct net_device *dev)
 	dev->flags		= 0;
 	dev->header_ops		= &dlci_header_ops;
 	dev->netdev_ops		= &dlci_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->needs_free_netdev	= true;
 
 	dlp->receive		= dlci_receive;
 

diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
@@ -1106,7 +1106,7 @@ static int fr_add_pvc(struct net_device *frad, unsigned int dlci, int type)
 		return -EIO;
 	}
 
-	dev->destructor = free_netdev;
+	dev->needs_free_netdev = true;
 	*get_dev_p(pvc, type) = dev;
 	if (!used) {
 		state(hdlc)->dce_changed = 1;