netdev - [PATCH net-next 3/9] net: use netif_disable_lro in ipv6_add

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Message-ID: <20250325213056.332902-4-sdf@fomichev.me>
Date: Tue, 25 Mar 2025 14:30:50 -0700
From: Stanislav Fomichev <sdf@...ichev.me>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	Cosmin Ratiu <cratiu@...dia.com>
Subject: [PATCH net-next 3/9] net: use netif_disable_lro in ipv6_add_dev

ipv6_add_dev might call dev_disable_lro which unconditionally grabs
instance lock, so it will deadlock during NETDEV_REGISTER. Switch
to netif_disable_lro.

Make sure all callers hold the instance lock as well.

Cc: Cosmin Ratiu <cratiu@...dia.com>
Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations")
Signed-off-by: Stanislav Fomichev <sdf@...ichev.me>
---
 include/linux/netdevice.h |  1 +
 net/core/dev.h            |  1 -
 net/ipv6/addrconf.c       | 17 +++++++++++++----
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fa79145518d1..b2b4e31806d5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3386,6 +3386,7 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex);
 struct net_device *__dev_get_by_index(struct net *net, int ifindex);
 struct net_device *netdev_get_by_index(struct net *net, int ifindex,
 				       netdevice_tracker *tracker, gfp_t gfp);
+struct net_device *netdev_get_by_index_lock(struct net *net, int ifindex);
 struct net_device *netdev_get_by_name(struct net *net, const char *name,
 				      netdevice_tracker *tracker, gfp_t gfp);
 struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);
diff --git a/net/core/dev.h b/net/core/dev.h
index 7ee203395d8e..8d35860f2e89 100644
--- a/net/core/dev.h
+++ b/net/core/dev.h
@@ -28,7 +28,6 @@ struct napi_struct *
 netdev_napi_by_id_lock(struct net *net, unsigned int napi_id);
 struct net_device *dev_get_by_napi_id(unsigned int napi_id);
 
-struct net_device *netdev_get_by_index_lock(struct net *net, int ifindex);
 struct net_device *__netdev_put_lock(struct net_device *dev);
 struct net_device *
 netdev_xa_find_lock(struct net *net, struct net_device *dev,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index ac8cc1076536..665184d2adce 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -80,6 +80,7 @@
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/l3mdev.h>
+#include <net/netdev_lock.h>
 #include <linux/if_tunnel.h>
 #include <linux/rtnetlink.h>
 #include <linux/netconf.h>
@@ -377,6 +378,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
 	int err = -ENOMEM;
 
 	ASSERT_RTNL();
+	netdev_ops_assert_locked(dev);
 
 	if (dev->mtu < IPV6_MIN_MTU && dev != blackhole_netdev)
 		return ERR_PTR(-EINVAL);
@@ -402,7 +404,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
 		return ERR_PTR(err);
 	}
 	if (ndev->cnf.forwarding)
-		dev_disable_lro(dev);
+		netif_disable_lro(dev);
 	/* We refer to the device */
 	netdev_hold(dev, &ndev->dev_tracker, GFP_KERNEL);
 
@@ -3151,11 +3153,12 @@ int addrconf_add_ifaddr(struct net *net, void __user *arg)
 	cfg.plen = ireq.ifr6_prefixlen;
 
 	rtnl_net_lock(net);
-	dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
+	dev = netdev_get_by_index_lock(net, ireq.ifr6_ifindex);
 	if (dev)
 		err = inet6_addr_add(net, dev, &cfg, 0, 0, NULL);
 	else
 		err = -ENODEV;
+	netdev_unlock(dev);
 	rtnl_net_unlock(net);
 	return err;
 }
@@ -5022,11 +5025,11 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	rtnl_net_lock(net);
 
-	dev =  __dev_get_by_index(net, ifm->ifa_index);
+	dev = netdev_get_by_index_lock(net, ifm->ifa_index);
 	if (!dev) {
 		NL_SET_ERR_MSG_MOD(extack, "Unable to find the interface");
 		err = -ENODEV;
-		goto unlock;
+		goto unlock_rtnl;
 	}
 
 	idev = ipv6_find_idev(dev);
@@ -5065,6 +5068,8 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 	in6_ifa_put(ifa);
 unlock:
+	netdev_unlock(dev);
+unlock_rtnl:
 	rtnl_net_unlock(net);
 
 	return err;
@@ -6503,7 +6508,9 @@ static int addrconf_sysctl_addr_gen_mode(const struct ctl_table *ctl, int write,
 
 			if (idev->cnf.addr_gen_mode != new_val) {
 				WRITE_ONCE(idev->cnf.addr_gen_mode, new_val);
+				netdev_lock_ops(idev->dev);
 				addrconf_init_auto_addrs(idev->dev);
+				netdev_unlock_ops(idev->dev);
 			}
 		} else if (&net->ipv6.devconf_all->addr_gen_mode == ctl->data) {
 			struct net_device *dev;
@@ -6515,7 +6522,9 @@ static int addrconf_sysctl_addr_gen_mode(const struct ctl_table *ctl, int write,
 				    idev->cnf.addr_gen_mode != new_val) {
 					WRITE_ONCE(idev->cnf.addr_gen_mode,
 						  new_val);
+					netdev_lock_ops(idev->dev);
 					addrconf_init_auto_addrs(idev->dev);
+					netdev_unlock_ops(idev->dev);
 				}
 			}
 		}
-- 
2.48.1