1 files changed, 138 insertions, 114 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 07274619b9ea..e04544ac4b45 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -77,7 +77,12 @@ struct ipmr_result {
  * Note that the changes are semaphored via rtnl_lock.
  */
 
-static DEFINE_RWLOCK(mrt_lock);
+static DEFINE_SPINLOCK(mrt_lock);
+
+static struct net_device *vif_dev_read(const struct vif_device *vif)
+{
+	return rcu_dereference(vif->dev);
+}
 
 /* Multicast router control variables */
 
@@ -100,11 +105,11 @@ static void ipmr_free_table(struct mr_table *mrt);
 static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 			  struct net_device *dev, struct sk_buff *skb,
 			  struct mfc_cache *cache, int local);
-static int ipmr_cache_report(struct mr_table *mrt,
+static int ipmr_cache_report(const struct mr_table *mrt,
 			     struct sk_buff *pkt, vifi_t vifi, int assert);
 static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
 				 int cmd);
-static void igmpmsg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt);
+static void igmpmsg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt);
 static void mroute_clean_tables(struct mr_table *mrt, int flags);
 static void ipmr_expire_process(struct timer_list *t);
 
@@ -256,7 +261,9 @@ static int __net_init ipmr_rules_init(struct net *net)
 	return 0;
 
 err2:
+	rtnl_lock();
 	ipmr_free_table(mrt);
+	rtnl_unlock();
 err1:
 	fib_rules_unregister(ops);
 	return err;
@@ -266,13 +273,12 @@ static void __net_exit ipmr_rules_exit(struct net *net)
 {
 	struct mr_table *mrt, *next;
 
-	rtnl_lock();
+	ASSERT_RTNL();
 	list_for_each_entry_safe(mrt, next, &net->ipv4.mr_tables, list) {
 		list_del(&mrt->list);
 		ipmr_free_table(mrt);
 	}
 	fib_rules_unregister(net->ipv4.mr_rules_ops);
-	rtnl_unlock();
 }
 
 static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -328,10 +334,9 @@ static int __net_init ipmr_rules_init(struct net *net)
 
 static void __net_exit ipmr_rules_exit(struct net *net)
 {
-	rtnl_lock();
+	ASSERT_RTNL();
 	ipmr_free_table(net->ipv4.mrt);
 	net->ipv4.mrt = NULL;
-	rtnl_unlock();
 }
 
 static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -356,7 +361,7 @@ static inline int ipmr_hash_cmp(struct rhashtable_compare_arg *arg,
 				const void *ptr)
 {
 	const struct mfc_cache_cmp_arg *cmparg = arg->key;
-	struct mfc_cache *c = (struct mfc_cache *)ptr;
+	const struct mfc_cache *c = ptr;
 
 	return cmparg->mfc_mcastgrp != c->mfc_mcastgrp ||
 	       cmparg->mfc_origin != c->mfc_origin;
@@ -501,11 +506,15 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, struct net_device *dev)
 		return err;
 	}
 
-	read_lock(&mrt_lock);
 	dev->stats.tx_bytes += skb->len;
 	dev->stats.tx_packets++;
-	ipmr_cache_report(mrt, skb, mrt->mroute_reg_vif_num, IGMPMSG_WHOLEPKT);
-	read_unlock(&mrt_lock);
+	rcu_read_lock();
+
+	/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */
+	ipmr_cache_report(mrt, skb, READ_ONCE(mrt->mroute_reg_vif_num),
+			  IGMPMSG_WHOLEPKT);
+
+	rcu_read_unlock();
 	kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
@@ -572,6 +581,7 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
 {
 	struct net_device *reg_dev = NULL;
 	struct iphdr *encap;
+	int vif_num;
 
 	encap = (struct iphdr *)(skb_transport_header(skb) + pimlen);
 	/* Check that:
@@ -584,11 +594,10 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
 	    ntohs(encap->tot_len) + pimlen > skb->len)
 		return 1;
 
-	read_lock(&mrt_lock);
-	if (mrt->mroute_reg_vif_num >= 0)
-		reg_dev = mrt->vif_table[mrt->mroute_reg_vif_num].dev;
-	read_unlock(&mrt_lock);
-
+	/* Pairs with WRITE_ONCE() in vif_add()/vid_delete() */
+	vif_num = READ_ONCE(mrt->mroute_reg_vif_num);
+	if (vif_num >= 0)
+		reg_dev = vif_dev_read(&mrt->vif_table[vif_num]);
 	if (!reg_dev)
 		return 1;
 
@@ -614,10 +623,11 @@ static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
 static int call_ipmr_vif_entry_notifiers(struct net *net,
 					 enum fib_event_type event_type,
 					 struct vif_device *vif,
+					 struct net_device *vif_dev,
 					 vifi_t vif_index, u32 tb_id)
 {
 	return mr_call_vif_notifiers(net, RTNL_FAMILY_IPMR, event_type,
-				     vif, vif_index, tb_id,
+				     vif, vif_dev, vif_index, tb_id,
 				     &net->ipv4.ipmr_seq);
 }
 
@@ -649,22 +659,19 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
 
 	v = &mrt->vif_table[vifi];
 
-	if (VIF_EXISTS(mrt, vifi))
-		call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, vifi,
-					      mrt->id);
-
-	write_lock_bh(&mrt_lock);
-	dev = v->dev;
-	v->dev = NULL;
-
-	if (!dev) {
-		write_unlock_bh(&mrt_lock);
+	dev = rtnl_dereference(v->dev);
+	if (!dev)
 		return -EADDRNOTAVAIL;
-	}
 
-	if (vifi == mrt->mroute_reg_vif_num)
-		mrt->mroute_reg_vif_num = -1;
+	spin_lock(&mrt_lock);
+	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, dev,
+				      vifi, mrt->id);
+	RCU_INIT_POINTER(v->dev, NULL);
 
+	if (vifi == mrt->mroute_reg_vif_num) {
+		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */
+		WRITE_ONCE(mrt->mroute_reg_vif_num, -1);
+	}
 	if (vifi + 1 == mrt->maxvif) {
 		int tmp;
 
@@ -672,10 +679,10 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
 			if (VIF_EXISTS(mrt, tmp))
 				break;
 		}
-		mrt->maxvif = tmp+1;
+		WRITE_ONCE(mrt->maxvif, tmp + 1);
 	}
 
-	write_unlock_bh(&mrt_lock);
+	spin_unlock(&mrt_lock);
 
 	dev_set_allmulti(dev, -1);
 
@@ -691,7 +698,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify,
 	if (v->flags & (VIFF_TUNNEL | VIFF_REGISTER) && !notify)
 		unregister_netdevice_queue(dev, head);
 
-	dev_put_track(dev, &v->dev_tracker);
+	netdev_put(dev, &v->dev_tracker);
 	return 0;
 }
 
@@ -777,7 +784,7 @@ out:
 	spin_unlock(&mfc_unres_lock);
 }
 
-/* Fill oifs list. It is called under write locked mrt_lock. */
+/* Fill oifs list. It is called under locked mrt_lock. */
 static void ipmr_update_thresholds(struct mr_table *mrt, struct mr_mfc *cache,
 				   unsigned char *ttls)
 {
@@ -889,15 +896,18 @@ static int vif_add(struct net *net, struct mr_table *mrt,
 	v->remote = vifc->vifc_rmt_addr.s_addr;
 
 	/* And finish update writing critical data */
-	write_lock_bh(&mrt_lock);
-	v->dev = dev;
+	spin_lock(&mrt_lock);
+	rcu_assign_pointer(v->dev, dev);
 	netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC);
-	if (v->flags & VIFF_REGISTER)
-		mrt->mroute_reg_vif_num = vifi;
+	if (v->flags & VIFF_REGISTER) {
+		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */
+		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);
+	}
 	if (vifi+1 > mrt->maxvif)
-		mrt->maxvif = vifi+1;
-	write_unlock_bh(&mrt_lock);
-	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, vifi, mrt->id);
+		WRITE_ONCE(mrt->maxvif, vifi + 1);
+	spin_unlock(&mrt_lock);
+	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,
+				      vifi, mrt->id);
 	return 0;
 }
 
@@ -994,16 +1004,18 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
 
 			rtnl_unicast(skb, net, NETLINK_CB(skb).portid);
 		} else {
+			rcu_read_lock();
 			ip_mr_forward(net, mrt, skb->dev, skb, c, 0);
+			rcu_read_unlock();
 		}
 	}
 }
 
 /* Bounce a cache query up to mrouted and netlink.
  *
- * Called under mrt_lock.
+ * Called under rcu_read_lock().
  */
-static int ipmr_cache_report(struct mr_table *mrt,
+static int ipmr_cache_report(const struct mr_table *mrt,
 			     struct sk_buff *pkt, vifi_t vifi, int assert)
 {
 	const int ihl = ip_hdrlen(pkt);
@@ -1038,8 +1050,11 @@ static int ipmr_cache_report(struct mr_table *mrt,
 			msg->im_vif = vifi;
 			msg->im_vif_hi = vifi >> 8;
 		} else {
-			msg->im_vif = mrt->mroute_reg_vif_num;
-			msg->im_vif_hi = mrt->mroute_reg_vif_num >> 8;
+			/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */
+			int vif_num = READ_ONCE(mrt->mroute_reg_vif_num);
+
+			msg->im_vif = vif_num;
+			msg->im_vif_hi = vif_num >> 8;
 		}
 		ip_hdr(skb)->ihl = sizeof(struct iphdr) >> 2;
 		ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(pkt)->tot_len) +
@@ -1064,10 +1079,8 @@ static int ipmr_cache_report(struct mr_table *mrt,
 		skb->transport_header = skb->network_header;
 	}
 
-	rcu_read_lock();
 	mroute_sk = rcu_dereference(mrt->mroute_sk);
 	if (!mroute_sk) {
-		rcu_read_unlock();
 		kfree_skb(skb);
 		return -EINVAL;
 	}
@@ -1076,7 +1089,7 @@ static int ipmr_cache_report(struct mr_table *mrt,
 
 	/* Deliver to mrouted */
 	ret = sock_queue_rcv_skb(mroute_sk, skb);
-	rcu_read_unlock();
+
 	if (ret < 0) {
 		net_warn_ratelimited("mroute: pending queue full, dropping entries\n");
 		kfree_skb(skb);
@@ -1086,6 +1099,7 @@ static int ipmr_cache_report(struct mr_table *mrt,
 }
 
 /* Queue a packet for resolution. It gets locked cache entry! */
+/* Called under rcu_read_lock() */
 static int ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi,
 				 struct sk_buff *skb, struct net_device *dev)
 {
@@ -1198,12 +1212,12 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
 				   mfc->mfcc_mcastgrp.s_addr, parent);
 	rcu_read_unlock();
 	if (c) {
-		write_lock_bh(&mrt_lock);
+		spin_lock(&mrt_lock);
 		c->_c.mfc_parent = mfc->mfcc_parent;
 		ipmr_update_thresholds(mrt, &c->_c, mfc->mfcc_ttls);
 		if (!mrtsock)
 			c->_c.mfc_flags |= MFC_STATIC;
-		write_unlock_bh(&mrt_lock);
+		spin_unlock(&mrt_lock);
 		call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE, c,
 					      mrt->id);
 		mroute_netlink_event(mrt, c, RTM_NEWROUTE);
@@ -1534,7 +1548,8 @@ out:
 }
 
 /* Getsock opt support for the multicast routing system. */
-int ip_mroute_getsockopt(struct sock *sk, int optname, char __user *optval, int __user *optlen)
+int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
+			 sockptr_t optlen)
 {
 	int olr;
 	int val;
@@ -1565,14 +1580,14 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, char __user *optval, int
 		return -ENOPROTOOPT;
 	}
 
-	if (get_user(olr, optlen))
+	if (copy_from_sockptr(&olr, optlen, sizeof(int)))
 		return -EFAULT;
 	olr = min_t(unsigned int, olr, sizeof(int));
 	if (olr < 0)
 		return -EINVAL;
-	if (put_user(olr, optlen))
+	if (copy_to_sockptr(optlen, &olr, sizeof(int)))
 		return -EFAULT;
-	if (copy_to_user(optval, &val, olr))
+	if (copy_to_sockptr(optval, &val, olr))
 		return -EFAULT;
 	return 0;
 }
@@ -1598,20 +1613,20 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
 		if (vr.vifi >= mrt->maxvif)
 			return -EINVAL;
 		vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
-		read_lock(&mrt_lock);
+		rcu_read_lock();
 		vif = &mrt->vif_table[vr.vifi];
 		if (VIF_EXISTS(mrt, vr.vifi)) {
-			vr.icount = vif->pkt_in;
-			vr.ocount = vif->pkt_out;
-			vr.ibytes = vif->bytes_in;
-			vr.obytes = vif->bytes_out;
-			read_unlock(&mrt_lock);
+			vr.icount = READ_ONCE(vif->pkt_in);
+			vr.ocount = READ_ONCE(vif->pkt_out);
+			vr.ibytes = READ_ONCE(vif->bytes_in);
+			vr.obytes = READ_ONCE(vif->bytes_out);
+			rcu_read_unlock();
 
 			if (copy_to_user(arg, &vr, sizeof(vr)))
 				return -EFAULT;
 			return 0;
 		}
-		read_unlock(&mrt_lock);
+		rcu_read_unlock();
 		return -EADDRNOTAVAIL;
 	case SIOCGETSGCNT:
 		if (copy_from_user(&sr, arg, sizeof(sr)))
@@ -1673,20 +1688,20 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 		if (vr.vifi >= mrt->maxvif)
 			return -EINVAL;
 		vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
-		read_lock(&mrt_lock);
+		rcu_read_lock();
 		vif = &mrt->vif_table[vr.vifi];
 		if (VIF_EXISTS(mrt, vr.vifi)) {
-			vr.icount = vif->pkt_in;
-			vr.ocount = vif->pkt_out;
-			vr.ibytes = vif->bytes_in;
-			vr.obytes = vif->bytes_out;
-			read_unlock(&mrt_lock);
+			vr.icount = READ_ONCE(vif->pkt_in);
+			vr.ocount = READ_ONCE(vif->pkt_out);
+			vr.ibytes = READ_ONCE(vif->bytes_in);
+			vr.obytes = READ_ONCE(vif->bytes_out);
+			rcu_read_unlock();
 
 			if (copy_to_user(arg, &vr, sizeof(vr)))
 				return -EFAULT;
 			return 0;
 		}
-		read_unlock(&mrt_lock);
+		rcu_read_unlock();
 		return -EADDRNOTAVAIL;
 	case SIOCGETSGCNT:
 		if (copy_from_user(&sr, arg, sizeof(sr)))
@@ -1726,7 +1741,7 @@ static int ipmr_device_event(struct notifier_block *this, unsigned long event, v
 	ipmr_for_each_table(mrt, net) {
 		v = &mrt->vif_table[0];
 		for (ct = 0; ct < mrt->maxvif; ct++, v++) {
-			if (v->dev == dev)
+			if (rcu_access_pointer(v->dev) == dev)
 				vif_delete(mrt, ct, 1, NULL);
 		}
 	}
@@ -1804,26 +1819,28 @@ static bool ipmr_forward_offloaded(struct sk_buff *skb, struct mr_table *mrt,
 }
 #endif
 
-/* Processing handlers for ipmr_forward */
+/* Processing handlers for ipmr_forward, under rcu_read_lock() */
 
 static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 			    int in_vifi, struct sk_buff *skb, int vifi)
 {
 	const struct iphdr *iph = ip_hdr(skb);
 	struct vif_device *vif = &mrt->vif_table[vifi];
+	struct net_device *vif_dev;
 	struct net_device *dev;
 	struct rtable *rt;
 	struct flowi4 fl4;
 	int    encap = 0;
 
-	if (!vif->dev)
+	vif_dev = vif_dev_read(vif);
+	if (!vif_dev)
 		goto out_free;
 
 	if (vif->flags & VIFF_REGISTER) {
-		vif->pkt_out++;
-		vif->bytes_out += skb->len;
-		vif->dev->stats.tx_bytes += skb->len;
-		vif->dev->stats.tx_packets++;
+		WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
+		WRITE_ONCE(vif->bytes_out, vif->bytes_out + skb->len);
+		vif_dev->stats.tx_bytes += skb->len;
+		vif_dev->stats.tx_packets++;
 		ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
 		goto out_free;
 	}
@@ -1868,8 +1885,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		goto out_free;
 	}
 
-	vif->pkt_out++;
-	vif->bytes_out += skb->len;
+	WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
+	WRITE_ONCE(vif->bytes_out, vif->bytes_out + skb->len);
 
 	skb_dst_drop(skb);
 	skb_dst_set(skb, &rt->dst);
@@ -1881,8 +1898,8 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 	if (vif->flags & VIFF_TUNNEL) {
 		ip_encap(net, skb, vif->local, vif->remote);
 		/* FIXME: extra output firewall step used to be here. --RR */
-		vif->dev->stats.tx_packets++;
-		vif->dev->stats.tx_bytes += skb->len;
+		vif_dev->stats.tx_packets++;
+		vif_dev->stats.tx_bytes += skb->len;
 	}
 
 	IPCB(skb)->flags |= IPSKB_FORWARDED;
@@ -1906,18 +1923,20 @@ out_free:
 	kfree_skb(skb);
 }
 
-static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)
+/* Called with mrt_lock or rcu_read_lock() */
+static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev)
 {
 	int ct;
-
-	for (ct = mrt->maxvif-1; ct >= 0; ct--) {
-		if (mrt->vif_table[ct].dev == dev)
+	/* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */
+	for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) {
+		if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)
 			break;
 	}
 	return ct;
 }
 
 /* "local" means that we should preserve one skb (for local delivery) */
+/* Called uner rcu_read_lock() */
 static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 			  struct net_device *dev, struct sk_buff *skb,
 			  struct mfc_cache *c, int local)
@@ -1944,7 +1963,7 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 	}
 
 	/* Wrong interface: drop packet and (maybe) send PIM assert. */
-	if (mrt->vif_table[vif].dev != dev) {
+	if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev) {
 		if (rt_is_output_route(skb_rtable(skb))) {
 			/* It is our own packet, looped back.
 			 * Very complicated situation...
@@ -1983,8 +2002,10 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 	}
 
 forward:
-	mrt->vif_table[vif].pkt_in++;
-	mrt->vif_table[vif].bytes_in += skb->len;
+	WRITE_ONCE(mrt->vif_table[vif].pkt_in,
+		   mrt->vif_table[vif].pkt_in + 1);
+	WRITE_ONCE(mrt->vif_table[vif].bytes_in,
+		   mrt->vif_table[vif].bytes_in + skb->len);
 
 	/* Forward the frame */
 	if (c->mfc_origin == htonl(INADDR_ANY) &&
@@ -2140,22 +2161,14 @@ int ip_mr_input(struct sk_buff *skb)
 			skb = skb2;
 		}
 
-		read_lock(&mrt_lock);
 		vif = ipmr_find_vif(mrt, dev);
-		if (vif >= 0) {
-			int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev);
-			read_unlock(&mrt_lock);
-
-			return err2;
-		}
-		read_unlock(&mrt_lock);
+		if (vif >= 0)
+			return ipmr_cache_unresolved(mrt, vif, skb, dev);
 		kfree_skb(skb);
 		return -ENODEV;
 	}
 
-	read_lock(&mrt_lock);
 	ip_mr_forward(net, mrt, dev, skb, cache, local);
-	read_unlock(&mrt_lock);
 
 	if (local)
 		return ip_local_deliver(skb);
@@ -2252,18 +2265,15 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb,
 		int vif = -1;
 
 		dev = skb->dev;
-		read_lock(&mrt_lock);
 		if (dev)
 			vif = ipmr_find_vif(mrt, dev);
 		if (vif < 0) {
-			read_unlock(&mrt_lock);
 			rcu_read_unlock();
 			return -ENODEV;
 		}
 
 		skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr));
 		if (!skb2) {
-			read_unlock(&mrt_lock);
 			rcu_read_unlock();
 			return -ENOMEM;
 		}
@@ -2277,14 +2287,11 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb,
 		iph->daddr = daddr;
 		iph->version = 0;
 		err = ipmr_cache_unresolved(mrt, vif, skb2, dev);
-		read_unlock(&mrt_lock);
 		rcu_read_unlock();
 		return err;
 	}
 
-	read_lock(&mrt_lock);
 	err = mr_fill_mroute(mrt, skb, &cache->_c, rtm);
-	read_unlock(&mrt_lock);
 	rcu_read_unlock();
 	return err;
 }
@@ -2404,7 +2411,7 @@ static size_t igmpmsg_netlink_msgsize(size_t payloadlen)
 	return len;
 }
 
-static void igmpmsg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt)
+static void igmpmsg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt)
 {
 	struct net *net = read_pnet(&mrt->net);
 	struct nlmsghdr *nlh;
@@ -2744,18 +2751,21 @@ static bool ipmr_fill_table(struct mr_table *mrt, struct sk_buff *skb)
 
 static bool ipmr_fill_vif(struct mr_table *mrt, u32 vifid, struct sk_buff *skb)
 {
+	struct net_device *vif_dev;
 	struct nlattr *vif_nest;
 	struct vif_device *vif;
 
+	vif = &mrt->vif_table[vifid];
+	vif_dev = rtnl_dereference(vif->dev);
 	/* if the VIF doesn't exist just continue */
-	if (!VIF_EXISTS(mrt, vifid))
+	if (!vif_dev)
 		return true;
 
-	vif = &mrt->vif_table[vifid];
 	vif_nest = nla_nest_start_noflag(skb, IPMRA_VIF);
 	if (!vif_nest)
 		return false;
-	if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif->dev->ifindex) ||
+
+	if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif_dev->ifindex) ||
 	    nla_put_u32(skb, IPMRA_VIFA_VIF_ID, vifid) ||
 	    nla_put_u16(skb, IPMRA_VIFA_FLAGS, vif->flags) ||
 	    nla_put_u64_64bit(skb, IPMRA_VIFA_BYTES_IN, vif->bytes_in,
@@ -2887,7 +2897,7 @@ out:
  */
 
 static void *ipmr_vif_seq_start(struct seq_file *seq, loff_t *pos)
-	__acquires(mrt_lock)
+	__acquires(RCU)
 {
 	struct mr_vif_iter *iter = seq->private;
 	struct net *net = seq_file_net(seq);
@@ -2899,14 +2909,14 @@ static void *ipmr_vif_seq_start(struct seq_file *seq, loff_t *pos)
 
 	iter->mrt = mrt;
 
-	read_lock(&mrt_lock);
+	rcu_read_lock();
 	return mr_vif_seq_start(seq, pos);
 }
 
 static void ipmr_vif_seq_stop(struct seq_file *seq, void *v)
-	__releases(mrt_lock)
+	__releases(RCU)
 {
-	read_unlock(&mrt_lock);
+	rcu_read_unlock();
 }
 
 static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
@@ -2919,9 +2929,11 @@ static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
 			 "Interface      BytesIn  PktsIn  BytesOut PktsOut Flags Local    Remote\n");
 	} else {
 		const struct vif_device *vif = v;
-		const char *name =  vif->dev ?
-				    vif->dev->name : "none";
+		const struct net_device *vif_dev;
+		const char *name;
 
+		vif_dev = vif_dev_read(vif);
+		name = vif_dev ? vif_dev->name : "none";
 		seq_printf(seq,
 			   "%2td %-10s %8ld %7ld  %8ld %7ld %05X %08X %08X\n",
 			   vif - mrt->vif_table,
@@ -3017,7 +3029,7 @@ static int ipmr_dump(struct net *net, struct notifier_block *nb,
 		     struct netlink_ext_ack *extack)
 {
 	return mr_dump(net, nb, RTNL_FAMILY_IPMR, ipmr_rules_dump,
-		       ipmr_mr_table_iter, &mrt_lock, extack);
+		       ipmr_mr_table_iter, extack);
 }
 
 static const struct fib_notifier_ops ipmr_notifier_ops_template = {
@@ -3075,7 +3087,9 @@ static int __net_init ipmr_net_init(struct net *net)
 proc_cache_fail:
 	remove_proc_entry("ip_mr_vif", net->proc_net);
 proc_vif_fail:
+	rtnl_lock();
 	ipmr_rules_exit(net);
+	rtnl_unlock();
 #endif
 ipmr_rules_fail:
 	ipmr_notifier_exit(net);
@@ -3090,12 +3104,22 @@ static void __net_exit ipmr_net_exit(struct net *net)
 	remove_proc_entry("ip_mr_vif", net->proc_net);
 #endif
 	ipmr_notifier_exit(net);
-	ipmr_rules_exit(net);
+}
+
+static void __net_exit ipmr_net_exit_batch(struct list_head *net_list)
+{
+	struct net *net;
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		ipmr_rules_exit(net);
+	rtnl_unlock();
 }
 
 static struct pernet_operations ipmr_net_ops = {
 	.init = ipmr_net_init,
 	.exit = ipmr_net_exit,
+	.exit_batch = ipmr_net_exit_batch,
 };
 
 int __init ip_mr_init(void)