Merge branch 'net-core-fix-a-lockdep-splat-in-the-dev_addr_list'

Taehee Yoo says:

====================
net: core: fix a lockdep splat in the dev_addr_list.

This patchset is to avoid lockdep splat.

When a stacked interface graph is changed, netif_addr_lock() is called
recursively and it internally calls spin_lock_nested().
The parameter of spin_lock_nested() is 'dev->lower_level',
this is called subclass.
The problem of 'dev->lower_level' is that while 'dev->lower_level' is
being used as a subclass of spin_lock_nested(), its value can be changed.
So, spin_lock_nested() would be called recursively with the same
subclass value, the lockdep understands a deadlock.
In order to avoid this, a new variable is needed and it is going to be
used as a parameter of spin_lock_nested().
The first and second patch is a preparation patch for the third patch.
In the third patch, the problem will be fixed.

The first patch is to add __netdev_upper_dev_unlink().
An existed netdev_upper_dev_unlink() is renamed to
__netdev_upper_dev_unlink(). and netdev_upper_dev_unlink()
is added as an wrapper of this function.

The second patch is to add the netdev_nested_priv structure.
netdev_walk_all_{ upper | lower }_dev() pass both private functions
and "data" pointer to handle their own things.
At this point, the data pointer type is void *.
In order to make it easier to expand common variables and functions,
this new netdev_nested_priv structure is added.

The third patch is to add a new variable 'nested_level'
into the net_device structure.
This variable will be used as a parameter of spin_lock_nested() of
dev->addr_list_lock.
Due to this variable, it can avoid lockdep splat.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 159 insertions, 63 deletions

diff --git a/net/bridge/br_arp_nd_proxy.c b/net/bridge/br_arp_nd_proxy.c
index b18cdf03edb3..dfec65eca8a6 100644
--- a/net/bridge/br_arp_nd_proxy.c
+++ b/net/bridge/br_arp_nd_proxy.c
@@ -88,9 +88,10 @@ static void br_arp_send(struct net_bridge *br, struct net_bridge_port *p,
 	}
 }
 
-static int br_chk_addr_ip(struct net_device *dev, void *data)
+static int br_chk_addr_ip(struct net_device *dev,
+			  struct netdev_nested_priv *priv)
 {
-	__be32 ip = *(__be32 *)data;
+	__be32 ip = *(__be32 *)priv->data;
 	struct in_device *in_dev;
 	__be32 addr = 0;
 
@@ -107,11 +108,15 @@ static int br_chk_addr_ip(struct net_device *dev, void *data)
 
 static bool br_is_local_ip(struct net_device *dev, __be32 ip)
 {
-	if (br_chk_addr_ip(dev, &ip))
+	struct netdev_nested_priv priv = {
+		.data = (void *)&ip,
+	};
+
+	if (br_chk_addr_ip(dev, &priv))
 		return true;
 
 	/* check if ip is configured on upper dev */
-	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &ip))
+	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip, &priv))
 		return true;
 
 	return false;
@@ -361,9 +366,10 @@ static void br_nd_send(struct net_bridge *br, struct net_bridge_port *p,
 	}
 }
 
-static int br_chk_addr_ip6(struct net_device *dev, void *data)
+static int br_chk_addr_ip6(struct net_device *dev,
+			   struct netdev_nested_priv *priv)
 {
-	struct in6_addr *addr = (struct in6_addr *)data;
+	struct in6_addr *addr = (struct in6_addr *)priv->data;
 
 	if (ipv6_chk_addr(dev_net(dev), addr, dev, 0))
 		return 1;
@@ -374,11 +380,15 @@ static int br_chk_addr_ip6(struct net_device *dev, void *data)
 static bool br_is_local_ip6(struct net_device *dev, struct in6_addr *addr)
 
 {
-	if (br_chk_addr_ip6(dev, addr))
+	struct netdev_nested_priv priv = {
+		.data = (void *)addr,
+	};
+
+	if (br_chk_addr_ip6(dev, &priv))
 		return true;
 
 	/* check if ip is configured on upper dev */
-	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, addr))
+	if (netdev_walk_all_upper_dev_rcu(dev, br_chk_addr_ip6, &priv))
 		return true;
 
 	return false;
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 61c94cefa843..ee8780080be5 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -1360,7 +1360,7 @@ static int br_vlan_is_bind_vlan_dev(const struct net_device *dev)
 }
 
 static int br_vlan_is_bind_vlan_dev_fn(struct net_device *dev,
-				       __always_unused void *data)
+			       __always_unused struct netdev_nested_priv *priv)
 {
 	return br_vlan_is_bind_vlan_dev(dev);
 }
@@ -1383,9 +1383,9 @@ struct br_vlan_bind_walk_data {
 };
 
 static int br_vlan_match_bind_vlan_dev_fn(struct net_device *dev,
-					  void *data_in)
+					  struct netdev_nested_priv *priv)
 {
-	struct br_vlan_bind_walk_data *data = data_in;
+	struct br_vlan_bind_walk_data *data = priv->data;
 	int found = 0;
 
 	if (br_vlan_is_bind_vlan_dev(dev) &&
@@ -1403,10 +1403,13 @@ br_vlan_get_upper_bind_vlan_dev(struct net_device *dev, u16 vid)
 	struct br_vlan_bind_walk_data data = {
 		.vid = vid,
 	};
+	struct netdev_nested_priv priv = {
+		.data = (void *)&data,
+	};
 
 	rcu_read_lock();
 	netdev_walk_all_upper_dev_rcu(dev, br_vlan_match_bind_vlan_dev_fn,
-				      &data);
+				      &priv);
 	rcu_read_unlock();
 
 	return data.result;
@@ -1487,9 +1490,9 @@ struct br_vlan_link_state_walk_data {
 };
 
 static int br_vlan_link_state_change_fn(struct net_device *vlan_dev,
-					void *data_in)
+					struct netdev_nested_priv *priv)
 {
-	struct br_vlan_link_state_walk_data *data = data_in;
+	struct br_vlan_link_state_walk_data *data = priv->data;
 
 	if (br_vlan_is_bind_vlan_dev(vlan_dev))
 		br_vlan_set_vlan_dev_state(data->br, vlan_dev);
@@ -1503,10 +1506,13 @@ static void br_vlan_link_state_change(struct net_device *dev,
 	struct br_vlan_link_state_walk_data data = {
 		.br = br
 	};
+	struct netdev_nested_priv priv = {
+		.data = (void *)&data,
+	};
 
 	rcu_read_lock();
 	netdev_walk_all_upper_dev_rcu(dev, br_vlan_link_state_change_fn,
-				      &data);
+				      &priv);
 	rcu_read_unlock();
 }
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 266073e300b5..4906b44af850 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6812,9 +6812,10 @@ static struct netdev_adjacent *__netdev_find_adj(struct net_device *adj_dev,
 	return NULL;
 }
 
-static int ____netdev_has_upper_dev(struct net_device *upper_dev, void *data)
+static int ____netdev_has_upper_dev(struct net_device *upper_dev,
+				    struct netdev_nested_priv *priv)
 {
-	struct net_device *dev = data;
+	struct net_device *dev = (struct net_device *)priv->data;
 
 	return upper_dev == dev;
 }
@@ -6831,10 +6832,14 @@ static int ____netdev_has_upper_dev(struct net_device *upper_dev, void *data)
 bool netdev_has_upper_dev(struct net_device *dev,
 			  struct net_device *upper_dev)
 {
+	struct netdev_nested_priv priv = {
+		.data = (void *)upper_dev,
+	};
+
 	ASSERT_RTNL();
 
 	return netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
-					     upper_dev);
+					     &priv);
 }
 EXPORT_SYMBOL(netdev_has_upper_dev);
 
@@ -6851,8 +6856,12 @@ EXPORT_SYMBOL(netdev_has_upper_dev);
 bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
 				  struct net_device *upper_dev)
 {
+	struct netdev_nested_priv priv = {
+		.data = (void *)upper_dev,
+	};
+
 	return !!netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
-					       upper_dev);
+					       &priv);
 }
 EXPORT_SYMBOL(netdev_has_upper_dev_all_rcu);
 
@@ -6997,8 +7006,8 @@ static struct net_device *netdev_next_upper_dev_rcu(struct net_device *dev,
 
 static int __netdev_walk_all_upper_dev(struct net_device *dev,
 				       int (*fn)(struct net_device *dev,
-						 void *data),
-				       void *data)
+					 struct netdev_nested_priv *priv),
+				       struct netdev_nested_priv *priv)
 {
 	struct net_device *udev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
 	struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
@@ -7010,7 +7019,7 @@ static int __netdev_walk_all_upper_dev(struct net_device *dev,
 
 	while (1) {
 		if (now != dev) {
-			ret = fn(now, data);
+			ret = fn(now, priv);
 			if (ret)
 				return ret;
 		}
@@ -7046,8 +7055,8 @@ static int __netdev_walk_all_upper_dev(struct net_device *dev,
 
 int netdev_walk_all_upper_dev_rcu(struct net_device *dev,
 				  int (*fn)(struct net_device *dev,
-					    void *data),
-				  void *data)
+					    struct netdev_nested_priv *priv),
+				  struct netdev_nested_priv *priv)
 {
 	struct net_device *udev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
 	struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
@@ -7058,7 +7067,7 @@ int netdev_walk_all_upper_dev_rcu(struct net_device *dev,
 
 	while (1) {
 		if (now != dev) {
-			ret = fn(now, data);
+			ret = fn(now, priv);
 			if (ret)
 				return ret;
 		}
@@ -7094,10 +7103,15 @@ EXPORT_SYMBOL_GPL(netdev_walk_all_upper_dev_rcu);
 static bool __netdev_has_upper_dev(struct net_device *dev,
 				   struct net_device *upper_dev)
 {
+	struct netdev_nested_priv priv = {
+		.flags = 0,
+		.data = (void *)upper_dev,
+	};
+
 	ASSERT_RTNL();
 
 	return __netdev_walk_all_upper_dev(dev, ____netdev_has_upper_dev,
-					   upper_dev);
+					   &priv);
 }
 
 /**
@@ -7215,8 +7229,8 @@ static struct net_device *__netdev_next_lower_dev(struct net_device *dev,
 
 int netdev_walk_all_lower_dev(struct net_device *dev,
 			      int (*fn)(struct net_device *dev,
-					void *data),
-			      void *data)
+					struct netdev_nested_priv *priv),
+			      struct netdev_nested_priv *priv)
 {
 	struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
 	struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
@@ -7227,7 +7241,7 @@ int netdev_walk_all_lower_dev(struct net_device *dev,
 
 	while (1) {
 		if (now != dev) {
-			ret = fn(now, data);
+			ret = fn(now, priv);
 			if (ret)
 				return ret;
 		}
@@ -7262,8 +7276,8 @@ EXPORT_SYMBOL_GPL(netdev_walk_all_lower_dev);
 
 static int __netdev_walk_all_lower_dev(struct net_device *dev,
 				       int (*fn)(struct net_device *dev,
-						 void *data),
-				       void *data)
+					 struct netdev_nested_priv *priv),
+				       struct netdev_nested_priv *priv)
 {
 	struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
 	struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
@@ -7275,7 +7289,7 @@ static int __netdev_walk_all_lower_dev(struct net_device *dev,
 
 	while (1) {
 		if (now != dev) {
-			ret = fn(now, data);
+			ret = fn(now, priv);
 			if (ret)
 				return ret;
 		}
@@ -7364,22 +7378,34 @@ static u8 __netdev_lower_depth(struct net_device *dev)
 	return max_depth;
 }
 
-static int __netdev_update_upper_level(struct net_device *dev, void *data)
+static int __netdev_update_upper_level(struct net_device *dev,
+				       struct netdev_nested_priv *__unused)
 {
 	dev->upper_level = __netdev_upper_depth(dev) + 1;
 	return 0;
 }
 
-static int __netdev_update_lower_level(struct net_device *dev, void *data)
+static int __netdev_update_lower_level(struct net_device *dev,
+				       struct netdev_nested_priv *priv)
 {
 	dev->lower_level = __netdev_lower_depth(dev) + 1;
+
+#ifdef CONFIG_LOCKDEP
+	if (!priv)
+		return 0;
+
+	if (priv->flags & NESTED_SYNC_IMM)
+		dev->nested_level = dev->lower_level - 1;
+	if (priv->flags & NESTED_SYNC_TODO)
+		net_unlink_todo(dev);
+#endif
 	return 0;
 }
 
 int netdev_walk_all_lower_dev_rcu(struct net_device *dev,
 				  int (*fn)(struct net_device *dev,
-					    void *data),
-				  void *data)
+					    struct netdev_nested_priv *priv),
+				  struct netdev_nested_priv *priv)
 {
 	struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
 	struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
@@ -7390,7 +7416,7 @@ int netdev_walk_all_lower_dev_rcu(struct net_device *dev,
 
 	while (1) {
 		if (now != dev) {
-			ret = fn(now, data);
+			ret = fn(now, priv);
 			if (ret)
 				return ret;
 		}
@@ -7650,6 +7676,7 @@ static void __netdev_adjacent_dev_unlink_neighbour(struct net_device *dev,
 static int __netdev_upper_dev_link(struct net_device *dev,
 				   struct net_device *upper_dev, bool master,
 				   void *upper_priv, void *upper_info,
+				   struct netdev_nested_priv *priv,
 				   struct netlink_ext_ack *extack)
 {
 	struct netdev_notifier_changeupper_info changeupper_info = {
@@ -7706,9 +7733,9 @@ static int __netdev_upper_dev_link(struct net_device *dev,
 	__netdev_update_upper_level(dev, NULL);
 	__netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
 
-	__netdev_update_lower_level(upper_dev, NULL);
+	__netdev_update_lower_level(upper_dev, priv);
 	__netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
-				    NULL);
+				    priv);
 
 	return 0;
 
@@ -7733,8 +7760,13 @@ int netdev_upper_dev_link(struct net_device *dev,
 			  struct net_device *upper_dev,
 			  struct netlink_ext_ack *extack)
 {
+	struct netdev_nested_priv priv = {
+		.flags = NESTED_SYNC_IMM | NESTED_SYNC_TODO,
+		.data = NULL,
+	};
+
 	return __netdev_upper_dev_link(dev, upper_dev, false,
-				       NULL, NULL, extack);
+				       NULL, NULL, &priv, extack);
 }
 EXPORT_SYMBOL(netdev_upper_dev_link);
 
@@ -7757,21 +7789,19 @@ int netdev_master_upper_dev_link(struct net_device *dev,
 				 void *upper_priv, void *upper_info,
 				 struct netlink_ext_ack *extack)
 {
+	struct netdev_nested_priv priv = {
+		.flags = NESTED_SYNC_IMM | NESTED_SYNC_TODO,
+		.data = NULL,
+	};
+
 	return __netdev_upper_dev_link(dev, upper_dev, true,
-				       upper_priv, upper_info, extack);
+				       upper_priv, upper_info, &priv, extack);
 }
 EXPORT_SYMBOL(netdev_master_upper_dev_link);
 
-/**
- * netdev_upper_dev_unlink - Removes a link to upper device
- * @dev: device
- * @upper_dev: new upper device
- *
- * Removes a link to device which is upper to this one. The caller must hold
- * the RTNL lock.
- */
-void netdev_upper_dev_unlink(struct net_device *dev,
-			     struct net_device *upper_dev)
+static void __netdev_upper_dev_unlink(struct net_device *dev,
+				      struct net_device *upper_dev,
+				      struct netdev_nested_priv *priv)
 {
 	struct netdev_notifier_changeupper_info changeupper_info = {
 		.info = {
@@ -7796,9 +7826,28 @@ void netdev_upper_dev_unlink(struct net_device *dev,
 	__netdev_update_upper_level(dev, NULL);
 	__netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
 
-	__netdev_update_lower_level(upper_dev, NULL);
+	__netdev_update_lower_level(upper_dev, priv);
 	__netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
-				    NULL);
+				    priv);
+}
+
+/**
+ * netdev_upper_dev_unlink - Removes a link to upper device
+ * @dev: device
+ * @upper_dev: new upper device
+ *
+ * Removes a link to device which is upper to this one. The caller must hold
+ * the RTNL lock.
+ */
+void netdev_upper_dev_unlink(struct net_device *dev,
+			     struct net_device *upper_dev)
+{
+	struct netdev_nested_priv priv = {
+		.flags = NESTED_SYNC_TODO,
+		.data = NULL,
+	};
+
+	__netdev_upper_dev_unlink(dev, upper_dev, &priv);
 }
 EXPORT_SYMBOL(netdev_upper_dev_unlink);
 
@@ -7834,6 +7883,10 @@ int netdev_adjacent_change_prepare(struct net_device *old_dev,
 				   struct net_device *dev,
 				   struct netlink_ext_ack *extack)
 {
+	struct netdev_nested_priv priv = {
+		.flags = 0,
+		.data = NULL,
+	};
 	int err;
 
 	if (!new_dev)
@@ -7841,8 +7894,8 @@ int netdev_adjacent_change_prepare(struct net_device *old_dev,
 
 	if (old_dev && new_dev != old_dev)
 		netdev_adjacent_dev_disable(dev, old_dev);
-
-	err = netdev_upper_dev_link(new_dev, dev, extack);
+	err = __netdev_upper_dev_link(new_dev, dev, false, NULL, NULL, &priv,
+				      extack);
 	if (err) {
 		if (old_dev && new_dev != old_dev)
 			netdev_adjacent_dev_enable(dev, old_dev);
@@ -7857,6 +7910,11 @@ void netdev_adjacent_change_commit(struct net_device *old_dev,
 				   struct net_device *new_dev,
 				   struct net_device *dev)
 {
+	struct netdev_nested_priv priv = {
+		.flags = NESTED_SYNC_IMM | NESTED_SYNC_TODO,
+		.data = NULL,
+	};
+
 	if (!new_dev || !old_dev)
 		return;
 
@@ -7864,7 +7922,7 @@ void netdev_adjacent_change_commit(struct net_device *old_dev,
 		return;
 
 	netdev_adjacent_dev_enable(dev, old_dev);
-	netdev_upper_dev_unlink(old_dev, dev);
+	__netdev_upper_dev_unlink(old_dev, dev, &priv);
 }
 EXPORT_SYMBOL(netdev_adjacent_change_commit);
 
@@ -7872,13 +7930,18 @@ void netdev_adjacent_change_abort(struct net_device *old_dev,
 				  struct net_device *new_dev,
 				  struct net_device *dev)
 {
+	struct netdev_nested_priv priv = {
+		.flags = 0,
+		.data = NULL,
+	};
+
 	if (!new_dev)
 		return;
 
 	if (old_dev && new_dev != old_dev)
 		netdev_adjacent_dev_enable(dev, old_dev);
 
-	netdev_upper_dev_unlink(new_dev, dev);
+	__netdev_upper_dev_unlink(new_dev, dev, &priv);
 }
 EXPORT_SYMBOL(netdev_adjacent_change_abort);
 
@@ -10062,6 +10125,19 @@ static void netdev_wait_allrefs(struct net_device *dev)
 void netdev_run_todo(void)
 {
 	struct list_head list;
+#ifdef CONFIG_LOCKDEP
+	struct list_head unlink_list;
+
+	list_replace_init(&net_unlink_list, &unlink_list);
+
+	while (!list_empty(&unlink_list)) {
+		struct net_device *dev = list_first_entry(&unlink_list,
+							  struct net_device,
+							  unlink_list);
+		list_del(&dev->unlink_list);
+		dev->nested_level = dev->lower_level - 1;
+	}
+#endif
 
 	/* Snapshot list, allow later requests */
 	list_replace_init(&net_todo_list, &list);
@@ -10274,6 +10350,10 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	dev->gso_max_segs = GSO_MAX_SEGS;
 	dev->upper_level = 1;
 	dev->lower_level = 1;
+#ifdef CONFIG_LOCKDEP
+	dev->nested_level = 0;
+	INIT_LIST_HEAD(&dev->unlink_list);
+#endif
 
 	INIT_LIST_HEAD(&dev->napi_list);
 	INIT_LIST_HEAD(&dev->unreg_list);
diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
index 54cd568e7c2f..fa1c37ec40c9 100644
--- a/net/core/dev_addr_lists.c
+++ b/net/core/dev_addr_lists.c
@@ -637,7 +637,7 @@ int dev_uc_sync(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	err = __hw_addr_sync(&to->uc, &from->uc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -667,7 +667,7 @@ int dev_uc_sync_multiple(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	err = __hw_addr_sync_multiple(&to->uc, &from->uc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -700,7 +700,7 @@ void dev_uc_unsync(struct net_device *to, struct net_device *from)
 	 * larger.
 	 */
 	netif_addr_lock_bh(from);
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	__hw_addr_unsync(&to->uc, &from->uc, to->addr_len);
 	__dev_set_rx_mode(to);
 	netif_addr_unlock(to);
@@ -867,7 +867,7 @@ int dev_mc_sync(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	err = __hw_addr_sync(&to->mc, &from->mc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -897,7 +897,7 @@ int dev_mc_sync_multiple(struct net_device *to, struct net_device *from)
 	if (to->addr_len != from->addr_len)
 		return -EINVAL;
 
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	err = __hw_addr_sync_multiple(&to->mc, &from->mc, to->addr_len);
 	if (!err)
 		__dev_set_rx_mode(to);
@@ -922,7 +922,7 @@ void dev_mc_unsync(struct net_device *to, struct net_device *from)
 
 	/* See the above comments inside dev_uc_unsync(). */
 	netif_addr_lock_bh(from);
-	netif_addr_lock_nested(to);
+	netif_addr_lock(to);
 	__hw_addr_unsync(&to->mc, &from->mc, to->addr_len);
 	__dev_set_rx_mode(to);
 	netif_addr_unlock(to);