Merge branch 'ipv6-devconf-lockless'

Eric Dumazet says:

====================
ipv6: lockless accesses to devconf

- First patch puts in a cacheline_group the fields used in fast paths.

- Annotate all data races around idev->cnf fields.

- Last patch in this series removes RTNL use for RTM_GETNETCONF dumps.

v3: addressed Jakub Kicinski feedback in addrconf_disable_ipv6()
Added tags from Jiri and Florian.

v2: addressed Jiri Pirko feedback
- Added "ipv6: addrconf_disable_ipv6() optimizations"
and "ipv6: addrconf_disable_policy() optimization"
====================

Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/netronome/nfp/flower/action.c

···
 			set_tun->ttl = ip6_dst_hoplimit(dst);
 			dst_release(dst);
 		} else {
-			set_tun->ttl = net->ipv6.devconf_all->hop_limit;
+			set_tun->ttl = READ_ONCE(net->ipv6.devconf_all->hop_limit);
 		}
 #endif
 	} else {

drivers/net/usb/cdc_mbim.c

···
 	in6_dev = in6_dev_get(netdev);
 	if (!in6_dev)
 		goto out;
-	is_router = !!in6_dev->cnf.forwarding;
+	is_router = !!READ_ONCE(in6_dev->cnf.forwarding);
 	in6_dev_put(in6_dev);
 
 	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */

include/linux/ipv6.h

···
 #define _IPV6_H
 
 #include <uapi/linux/ipv6.h>
+#include <linux/cache.h>
 
 #define ipv6_optlen(p)  (((p)->hdrlen+1) << 3)
 #define ipv6_authlen(p) (((p)->hdrlen+2) << 2)
···
  * This structure contains configuration options per IPv6 link.
  */
 struct ipv6_devconf {
-	__s32		forwarding;
+	/* RX & TX fastpath fields. */
+	__cacheline_group_begin(ipv6_devconf_read_txrx);
+	__s32		disable_ipv6;
 	__s32		hop_limit;
 	__s32		mtu6;
+	__s32		forwarding;
+	__s32		disable_policy;
+	__s32		proxy_ndp;
+	__cacheline_group_end(ipv6_devconf_read_txrx);
+
 	__s32		accept_ra;
 	__s32		accept_redirects;
 	__s32		autoconf;
···
 	__s32		accept_ra_rt_info_max_plen;
 #endif
 #endif
-	__s32		proxy_ndp;
 	__s32		accept_source_route;
 	__s32		accept_ra_from_local;
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
···
 #ifdef CONFIG_IPV6_MROUTE
 	atomic_t	mc_forwarding;
 #endif
-	__s32		disable_ipv6;
 	__s32		drop_unicast_in_l2_multicast;
 	__s32		accept_dad;
 	__s32		force_tllao;
···
 #endif
 	__u32		enhanced_dad;
 	__u32		addr_gen_mode;
-	__s32		disable_policy;
 	__s32           ndisc_tclass;
 	__s32		rpl_seg_enabled;
 	__u32		ioam6_id;

include/net/addrconf.h

···
 	if (unlikely(!idev))
 		return true;
 
-	return !!idev->cnf.ignore_routes_with_linkdown;
+	return !!READ_ONCE(idev->cnf.ignore_routes_with_linkdown);
 }
 
 void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp);

include/net/ip6_route.h

···
 	rcu_read_lock();
 	idev = __in6_dev_get(dst->dev);
 	if (idev)
-		mtu = idev->cnf.mtu6;
+		mtu = READ_ONCE(idev->cnf.mtu6);
 	rcu_read_unlock();
 
 out:

include/net/ipv6.h

···
 	return 0;
 }
 
-static inline bool ipv6_accept_ra(struct inet6_dev *idev)
+static inline bool ipv6_accept_ra(const struct inet6_dev *idev)
 {
+	s32 accept_ra = READ_ONCE(idev->cnf.accept_ra);
+
 	/* If forwarding is enabled, RA are not accepted unless the special
 	 * hybrid mode (accept_ra=2) is enabled.
 	 */
-	return idev->cnf.forwarding ? idev->cnf.accept_ra == 2 :
-	    idev->cnf.accept_ra;
+	return READ_ONCE(idev->cnf.forwarding) ? accept_ra == 2 :
+		accept_ra;
 }
 
 #define IPV6_FRAG_HIGH_THRESH	(4 * 1024*1024)	/* 4194304 */

net/core/filter.c

···
 		return -ENODEV;
 
 	idev = __in6_dev_get_safely(dev);
-	if (unlikely(!idev || !idev->cnf.forwarding))
+	if (unlikely(!idev || !READ_ONCE(idev->cnf.forwarding)))
 		return BPF_FIB_LKUP_RET_FWD_DISABLED;
 
 	if (flags & BPF_FIB_LOOKUP_OUTPUT) {

net/ipv6/addrconf.c

···
 		goto out;
 
 	if ((all || type == NETCONFA_FORWARDING) &&
-	    nla_put_s32(skb, NETCONFA_FORWARDING, devconf->forwarding) < 0)
+	    nla_put_s32(skb, NETCONFA_FORWARDING,
+			READ_ONCE(devconf->forwarding)) < 0)
 		goto nla_put_failure;
 #ifdef CONFIG_IPV6_MROUTE
 	if ((all || type == NETCONFA_MC_FORWARDING) &&
···
 		goto nla_put_failure;
 #endif
 	if ((all || type == NETCONFA_PROXY_NEIGH) &&
-	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0)
+	    nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
+			READ_ONCE(devconf->proxy_ndp)) < 0)
 		goto nla_put_failure;
 
 	if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) &&
 	    nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
-			devconf->ignore_routes_with_linkdown) < 0)
+			READ_ONCE(devconf->ignore_routes_with_linkdown)) < 0)
 		goto nla_put_failure;
 
 out:
···
 	return res;
 }
 
-
 static int inet6_netconf_dump_devconf(struct sk_buff *skb,
 				      struct netlink_callback *cb)
 {
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
-	int h, s_h;
-	int idx, s_idx;
+	struct {
+		unsigned long ifindex;
+		unsigned int all_default;
+	} *ctx = (void *)cb->ctx;
 	struct net_device *dev;
 	struct inet6_dev *idev;
-	struct hlist_head *head;
+	int err = 0;
 
 	if (cb->strict_check) {
 		struct netlink_ext_ack *extack = cb->extack;
···
 		}
 	}
 
-	s_h = cb->args[0];
-	s_idx = idx = cb->args[1];
-
-	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
-		idx = 0;
-		head = &net->dev_index_head[h];
-		rcu_read_lock();
-		cb->seq = inet6_base_seq(net);
-		hlist_for_each_entry_rcu(dev, head, index_hlist) {
-			if (idx < s_idx)
-				goto cont;
-			idev = __in6_dev_get(dev);
-			if (!idev)
-				goto cont;
-
-			if (inet6_netconf_fill_devconf(skb, dev->ifindex,
-						       &idev->cnf,
-						       NETLINK_CB(cb->skb).portid,
-						       nlh->nlmsg_seq,
-						       RTM_NEWNETCONF,
-						       NLM_F_MULTI,
-						       NETCONFA_ALL) < 0) {
-				rcu_read_unlock();
-				goto done;
-			}
-			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
-cont:
-			idx++;
-		}
-		rcu_read_unlock();
-	}
-	if (h == NETDEV_HASHENTRIES) {
-		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
-					       net->ipv6.devconf_all,
-					       NETLINK_CB(cb->skb).portid,
-					       nlh->nlmsg_seq,
-					       RTM_NEWNETCONF, NLM_F_MULTI,
-					       NETCONFA_ALL) < 0)
+	rcu_read_lock();
+	for_each_netdev_dump(net, dev, ctx->ifindex) {
+		idev = __in6_dev_get(dev);
+		if (!idev)
+			continue;
+		err = inet6_netconf_fill_devconf(skb, dev->ifindex,
+					         &idev->cnf,
+						 NETLINK_CB(cb->skb).portid,
+						 nlh->nlmsg_seq,
+						 RTM_NEWNETCONF,
+						 NLM_F_MULTI,
+						 NETCONFA_ALL);
+		if (err < 0)
 			goto done;
-		else
-			h++;
 	}
-	if (h == NETDEV_HASHENTRIES + 1) {
-		if (inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
-					       net->ipv6.devconf_dflt,
-					       NETLINK_CB(cb->skb).portid,
-					       nlh->nlmsg_seq,
-					       RTM_NEWNETCONF, NLM_F_MULTI,
-					       NETCONFA_ALL) < 0)
+	if (ctx->all_default == 0) {
+		err = inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL,
+						 net->ipv6.devconf_all,
+						 NETLINK_CB(cb->skb).portid,
+						 nlh->nlmsg_seq,
+						 RTM_NEWNETCONF, NLM_F_MULTI,
+						 NETCONFA_ALL);
+		if (err < 0)
 			goto done;
-		else
-			h++;
+		ctx->all_default++;
+	}
+	if (ctx->all_default == 1) {
+		err = inet6_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT,
+						 net->ipv6.devconf_dflt,
+						 NETLINK_CB(cb->skb).portid,
+						 nlh->nlmsg_seq,
+						 RTM_NEWNETCONF, NLM_F_MULTI,
+						 NETCONFA_ALL);
+		if (err < 0)
+			goto done;
+		ctx->all_default++;
 	}
 done:
-	cb->args[0] = h;
-	cb->args[1] = idx;
-
-	return skb->len;
+	if (err < 0 && likely(skb->len))
+		err = skb->len;
+	rcu_read_unlock();
+	return err;
 }
 
 #ifdef CONFIG_SYSCTL
···
 		idev = __in6_dev_get(dev);
 		if (idev) {
 			int changed = (!idev->cnf.forwarding) ^ (!newf);
-			idev->cnf.forwarding = newf;
+
+			WRITE_ONCE(idev->cnf.forwarding, newf);
 			if (changed)
 				dev_forward_change(idev);
 		}
···
 
 	net = (struct net *)table->extra2;
 	old = *p;
-	*p = newf;
+	WRITE_ONCE(*p, newf);
 
 	if (p == &net->ipv6.devconf_dflt->forwarding) {
 		if ((!newf) ^ (!old))
···
 	if (p == &net->ipv6.devconf_all->forwarding) {
 		int old_dflt = net->ipv6.devconf_dflt->forwarding;
 
-		net->ipv6.devconf_dflt->forwarding = newf;
+		WRITE_ONCE(net->ipv6.devconf_dflt->forwarding, newf);
 		if ((!newf) ^ (!old_dflt))
 			inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
 						     NETCONFA_FORWARDING,
···
 		if (idev) {
 			int changed = (!idev->cnf.ignore_routes_with_linkdown) ^ (!newf);
 
-			idev->cnf.ignore_routes_with_linkdown = newf;
+			WRITE_ONCE(idev->cnf.ignore_routes_with_linkdown, newf);
 			if (changed)
 				inet6_netconf_notify_devconf(dev_net(dev),
 							     RTM_NEWNETCONF,
···
 
 	net = (struct net *)table->extra2;
 	old = *p;
-	*p = newf;
+	WRITE_ONCE(*p, newf);
 
 	if (p == &net->ipv6.devconf_dflt->ignore_routes_with_linkdown) {
 		if ((!newf) ^ (!old))
···
 	}
 
 	if (p == &net->ipv6.devconf_all->ignore_routes_with_linkdown) {
-		net->ipv6.devconf_dflt->ignore_routes_with_linkdown = newf;
+		WRITE_ONCE(net->ipv6.devconf_dflt->ignore_routes_with_linkdown, newf);
 		addrconf_linkdown_change(net, newf);
 		if ((!newf) ^ (!old))
 			inet6_netconf_notify_devconf(net,
···
 	in6_ifa_put(ifp);
 }
 
-static unsigned long ipv6_get_regen_advance(struct inet6_dev *idev)
+static unsigned long ipv6_get_regen_advance(const struct inet6_dev *idev)
 {
-	return idev->cnf.regen_min_advance + idev->cnf.regen_max_retry *
-			idev->cnf.dad_transmits *
-			max(NEIGH_VAR(idev->nd_parms, RETRANS_TIME), HZ/100) / HZ;
+	return READ_ONCE(idev->cnf.regen_min_advance) +
+		READ_ONCE(idev->cnf.regen_max_retry) *
+		READ_ONCE(idev->cnf.dad_transmits) *
+		max(NEIGH_VAR(idev->nd_parms, RETRANS_TIME), HZ/100) / HZ;
 }
 
 static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
···
 
 retry:
 	in6_dev_hold(idev);
-	if (idev->cnf.use_tempaddr <= 0) {
+	if (READ_ONCE(idev->cnf.use_tempaddr) <= 0) {
 		write_unlock_bh(&idev->lock);
 		pr_info("%s: use_tempaddr is disabled\n", __func__);
 		in6_dev_put(idev);
···
 		goto out;
 	}
 	spin_lock_bh(&ifp->lock);
-	if (ifp->regen_count++ >= idev->cnf.regen_max_retry) {
-		idev->cnf.use_tempaddr = -1;	/*XXX*/
+	if (ifp->regen_count++ >= READ_ONCE(idev->cnf.regen_max_retry)) {
+		WRITE_ONCE(idev->cnf.use_tempaddr, -1);	/*XXX*/
 		spin_unlock_bh(&ifp->lock);
 		write_unlock_bh(&idev->lock);
 		pr_warn("%s: regeneration time exceeded - disabled temporary address support\n",
···
 	 */
 	cnf_temp_preferred_lft = READ_ONCE(idev->cnf.temp_prefered_lft);
 	max_desync_factor = min_t(long,
-				  idev->cnf.max_desync_factor,
+				  READ_ONCE(idev->cnf.max_desync_factor),
 				  cnf_temp_preferred_lft - regen_advance);
 
 	if (unlikely(idev->desync_factor > max_desync_factor)) {
···
 
 	memset(&cfg, 0, sizeof(cfg));
 	cfg.valid_lft = min_t(__u32, ifp->valid_lft,
-			      idev->cnf.temp_valid_lft + age);
+			      READ_ONCE(idev->cnf.temp_valid_lft) + age);
 	cfg.preferred_lft = cnf_temp_preferred_lft + age - idev->desync_factor;
 	cfg.preferred_lft = min_t(__u32, if_public_preferred_lft, cfg.preferred_lft);
 	cfg.preferred_lft = min_t(__u32, cfg.valid_lft, cfg.preferred_lft);
···
 	return 0;
 }
 
-static bool ipv6_use_optimistic_addr(struct net *net,
-				     struct inet6_dev *idev)
+static bool ipv6_use_optimistic_addr(const struct net *net,
+				     const struct inet6_dev *idev)
 {
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	if (!idev)
 		return false;
-	if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
+	if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
+	    !READ_ONCE(idev->cnf.optimistic_dad))
 		return false;
-	if (!net->ipv6.devconf_all->use_optimistic && !idev->cnf.use_optimistic)
+	if (!READ_ONCE(net->ipv6.devconf_all->use_optimistic) &&
+	    !READ_ONCE(idev->cnf.use_optimistic))
 		return false;
 
 	return true;
···
 #endif
 }
 
-static bool ipv6_allow_optimistic_dad(struct net *net,
-				      struct inet6_dev *idev)
+static bool ipv6_allow_optimistic_dad(const struct net *net,
+				      const struct inet6_dev *idev)
 {
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	if (!idev)
 		return false;
-	if (!net->ipv6.devconf_all->optimistic_dad && !idev->cnf.optimistic_dad)
+	if (!READ_ONCE(net->ipv6.devconf_all->optimistic_dad) &&
+	    !READ_ONCE(idev->cnf.optimistic_dad))
 		return false;
 
 	return true;
···
 		 */
 		int preftmp = dst->prefs & (IPV6_PREFER_SRC_PUBLIC|IPV6_PREFER_SRC_TMP) ?
 				!!(dst->prefs & IPV6_PREFER_SRC_TMP) :
-				score->ifa->idev->cnf.use_tempaddr >= 2;
+				READ_ONCE(score->ifa->idev->cnf.use_tempaddr) >= 2;
 		ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ preftmp;
 		break;
 	    }
···
 		idev = __in6_dev_get(dst_dev);
 		if ((dst_type & IPV6_ADDR_MULTICAST) ||
 		    dst.scope <= IPV6_ADDR_SCOPE_LINKLOCAL ||
-		    (idev && idev->cnf.use_oif_addrs_only)) {
+		    (idev && READ_ONCE(idev->cnf.use_oif_addrs_only))) {
 			use_oif_addr = true;
 		}
 	}
···
 {
 	struct inet6_dev *idev = ifp->idev;
 	struct net *net = dev_net(idev->dev);
+	int max_addresses;
 
 	if (addrconf_dad_end(ifp)) {
 		in6_ifa_put(ifp);
···
 
 		spin_unlock_bh(&ifp->lock);
 
-		if (idev->cnf.max_addresses &&
-		    ipv6_count_addresses(idev) >=
-		    idev->cnf.max_addresses)
+		max_addresses = READ_ONCE(idev->cnf.max_addresses);
+		if (max_addresses &&
+		    ipv6_count_addresses(idev) >= max_addresses)
 			goto lock_errdad;
 
 		net_info_ratelimited("%s: generating new stable privacy address because of DAD conflict\n",
···
 		 * (TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR), respectively.
 		 */
 		age = (now - ift->cstamp) / HZ;
-		max_valid = idev->cnf.temp_valid_lft - age;
+		max_valid = READ_ONCE(idev->cnf.temp_valid_lft) - age;
 		if (max_valid < 0)
 			max_valid = 0;
 
-		max_prefered = idev->cnf.temp_prefered_lft -
+		max_prefered = READ_ONCE(idev->cnf.temp_prefered_lft) -
 			       idev->desync_factor - age;
 		if (max_prefered < 0)
 			max_prefered = 0;
···
 	if (list_empty(&idev->tempaddr_list) && (valid_lft || prefered_lft))
 		create = true;
 
-	if (create && idev->cnf.use_tempaddr > 0) {
+	if (create && READ_ONCE(idev->cnf.use_tempaddr) > 0) {
 		/* When a new public address is created as described
 		 * in [ADDRCONF], also create a new temporary address.
 		 */
···
 	int create = 0, update_lft = 0;
 
 	if (!ifp && valid_lft) {
-		int max_addresses = in6_dev->cnf.max_addresses;
+		int max_addresses = READ_ONCE(in6_dev->cnf.max_addresses);
 		struct ifa6_config cfg = {
 			.pfx = addr,
 			.plen = pinfo->prefix_len,
···
 		};
 
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
-		if ((net->ipv6.devconf_all->optimistic_dad ||
-		     in6_dev->cnf.optimistic_dad) &&
+		if ((READ_ONCE(net->ipv6.devconf_all->optimistic_dad) ||
+		     READ_ONCE(in6_dev->cnf.optimistic_dad)) &&
 		    !net->ipv6.devconf_all->forwarding && sllao)
 			cfg.ifa_flags |= IFA_F_OPTIMISTIC;
 #endif
···
 		 */
 		update_lft = !create && stored_lft;
 
-		if (update_lft && !in6_dev->cnf.ra_honor_pio_life) {
+		if (update_lft && !READ_ONCE(in6_dev->cnf.ra_honor_pio_life)) {
 			const u32 minimum_lft = min_t(u32,
 				stored_lft, MIN_VALID_LIFETIME);
 			valid_lft = max(valid_lft, minimum_lft);
···
 	struct inet6_ifaddr *ifp;
 
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
-	if ((dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad ||
-	     idev->cnf.optimistic_dad) &&
+	if ((READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->optimistic_dad) ||
+	     READ_ONCE(idev->cnf.optimistic_dad)) &&
 	    !dev_net(idev->dev)->ipv6.devconf_all->forwarding)
 		cfg.ifa_flags |= IFA_F_OPTIMISTIC;
 #endif
···
 
 		if (idev) {
 			rt6_mtu_change(dev, dev->mtu);
-			idev->cnf.mtu6 = dev->mtu;
+			WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
 			break;
 		}
 
···
 			if (idev->cnf.mtu6 != dev->mtu &&
 			    dev->mtu >= IPV6_MIN_MTU) {
 				rt6_mtu_change(dev, dev->mtu);
-				idev->cnf.mtu6 = dev->mtu;
+				WRITE_ONCE(idev->cnf.mtu6, dev->mtu);
 			}
 			WRITE_ONCE(idev->tstamp, jiffies);
 			inet6_ifinfo_notify(RTM_NEWLINK, idev);
···
 	 */
 	if (!unregister && !idev->cnf.disable_ipv6) {
 		/* aggregate the system setting and interface setting */
-		int _keep_addr = net->ipv6.devconf_all->keep_addr_on_down;
+		int _keep_addr = READ_ONCE(net->ipv6.devconf_all->keep_addr_on_down);
 
 		if (!_keep_addr)
-			_keep_addr = idev->cnf.keep_addr_on_down;
+			_keep_addr = READ_ONCE(idev->cnf.keep_addr_on_down);
 
 		keep_addr = (_keep_addr > 0);
 	}
···
 	struct inet6_dev *idev = from_timer(idev, t, rs_timer);
 	struct net_device *dev = idev->dev;
 	struct in6_addr lladdr;
+	int rtr_solicits;
 
 	write_lock(&idev->lock);
 	if (idev->dead || !(idev->if_flags & IF_READY))
···
 	if (idev->if_flags & IF_RA_RCVD)
 		goto out;
 
-	if (idev->rs_probes++ < idev->cnf.rtr_solicits || idev->cnf.rtr_solicits < 0) {
+	rtr_solicits = READ_ONCE(idev->cnf.rtr_solicits);
+
+	if (idev->rs_probes++ < rtr_solicits || rtr_solicits < 0) {
 		write_unlock(&idev->lock);
 		if (!ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
 			ndisc_send_rs(dev, &lladdr,
···
 
 		write_lock(&idev->lock);
 		idev->rs_interval = rfc3315_s14_backoff_update(
-			idev->rs_interval, idev->cnf.rtr_solicit_max_interval);
+				idev->rs_interval,
+				READ_ONCE(idev->cnf.rtr_solicit_max_interval));
 		/* The wait after the last probe can be shorter */
 		addrconf_mod_rs_timer(idev, (idev->rs_probes ==
-					     idev->cnf.rtr_solicits) ?
-				      idev->cnf.rtr_solicit_delay :
+					     READ_ONCE(idev->cnf.rtr_solicits)) ?
+				      READ_ONCE(idev->cnf.rtr_solicit_delay) :
 				      idev->rs_interval);
 	} else {
 		/*
···
  */
 static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
 {
-	unsigned long rand_num;
 	struct inet6_dev *idev = ifp->idev;
+	unsigned long rand_num;
 	u64 nonce;
 
 	if (ifp->flags & IFA_F_OPTIMISTIC)
 		rand_num = 0;
 	else
-		rand_num = get_random_u32_below(idev->cnf.rtr_solicit_delay ? : 1);
+		rand_num = get_random_u32_below(
+				READ_ONCE(idev->cnf.rtr_solicit_delay) ? : 1);
 
 	nonce = 0;
-	if (idev->cnf.enhanced_dad ||
-	    dev_net(idev->dev)->ipv6.devconf_all->enhanced_dad) {
+	if (READ_ONCE(idev->cnf.enhanced_dad) ||
+	    READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->enhanced_dad)) {
 		do
 			get_random_bytes(&nonce, 6);
 		while (nonce == 0);
 	}
 	ifp->dad_nonce = nonce;
-	ifp->dad_probes = idev->cnf.dad_transmits;
+	ifp->dad_probes = READ_ONCE(idev->cnf.dad_transmits);
 	addrconf_mod_dad_work(ifp, rand_num);
 }
 
···
 
 	net = dev_net(dev);
 	if (dev->flags&(IFF_NOARP|IFF_LOOPBACK) ||
-	    (net->ipv6.devconf_all->accept_dad < 1 &&
-	     idev->cnf.accept_dad < 1) ||
+	    (READ_ONCE(net->ipv6.devconf_all->accept_dad) < 1 &&
+	     READ_ONCE(idev->cnf.accept_dad) < 1) ||
 	    !(ifp->flags&IFA_F_TENTATIVE) ||
 	    ifp->flags & IFA_F_NODAD) {
 		bool send_na = false;
···
 		action = DAD_ABORT;
 		ifp->state = INET6_IFADDR_STATE_POSTDAD;
 
-		if ((dev_net(idev->dev)->ipv6.devconf_all->accept_dad > 1 ||
-		     idev->cnf.accept_dad > 1) &&
+		if ((READ_ONCE(dev_net(idev->dev)->ipv6.devconf_all->accept_dad) > 1 ||
+		     READ_ONCE(idev->cnf.accept_dad) > 1) &&
 		    !idev->cnf.disable_ipv6 &&
 		    !(ifp->flags & IFA_F_STABLE_PRIVACY)) {
 			struct in6_addr addr;
···
 			if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
 			    ipv6_addr_equal(&ifp->addr, &addr)) {
 				/* DAD failed for link-local based on MAC */
-				idev->cnf.disable_ipv6 = 1;
+				WRITE_ONCE(idev->cnf.disable_ipv6, 1);
 
 				pr_info("%s: IPv6 being disabled!\n",
 					ifp->idev->dev->name);
···
 	send_mld = ifp->scope == IFA_LINK && ipv6_lonely_lladdr(ifp);
 	send_rs = send_mld &&
 		  ipv6_accept_ra(ifp->idev) &&
-		  ifp->idev->cnf.rtr_solicits != 0 &&
+		  READ_ONCE(ifp->idev->cnf.rtr_solicits) != 0 &&
 		  (dev->flags & IFF_LOOPBACK) == 0 &&
 		  (dev->type != ARPHRD_TUNNEL) &&
 		  !netif_is_team_port(dev);
···
 
 	/* send unsolicited NA if enabled */
 	if (send_na &&
-	    (ifp->idev->cnf.ndisc_notify ||
-	     dev_net(dev)->ipv6.devconf_all->ndisc_notify)) {
+	    (READ_ONCE(ifp->idev->cnf.ndisc_notify) ||
+	     READ_ONCE(dev_net(dev)->ipv6.devconf_all->ndisc_notify))) {
 		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifp->addr,
 			      /*router=*/ !!ifp->idev->cnf.forwarding,
 			      /*solicited=*/ false, /*override=*/ true,
···
 		write_lock_bh(&ifp->idev->lock);
 		spin_lock(&ifp->lock);
 		ifp->idev->rs_interval = rfc3315_s14_backoff_init(
-			ifp->idev->cnf.rtr_solicit_interval);
+			READ_ONCE(ifp->idev->cnf.rtr_solicit_interval));
 		ifp->idev->rs_probes = 1;
 		ifp->idev->if_flags |= IF_RS_SENT;
 		addrconf_mod_rs_timer(ifp->idev, ifp->idev->rs_interval);
···
 		return -EINVAL;
 	}
 
-	if (idev->cnf.rtr_solicits == 0) {
+	if (READ_ONCE(idev->cnf.rtr_solicits) == 0) {
 		NL_SET_ERR_MSG(extack,
 			       "Router solicitation is disabled on device");
 		return -EINVAL;
···
 	if (update_rs) {
 		idev->if_flags |= IF_RS_SENT;
 		idev->rs_interval = rfc3315_s14_backoff_init(
-			idev->cnf.rtr_solicit_interval);
+			READ_ONCE(idev->cnf.rtr_solicit_interval));
 		idev->rs_probes = 1;
 		addrconf_mod_rs_timer(idev, idev->rs_interval);
 	}
···
 		idev = __in6_dev_get(dev);
 		if (idev) {
 			int changed = (!idev->cnf.disable_ipv6) ^ (!newf);
-			idev->cnf.disable_ipv6 = newf;
+
+			WRITE_ONCE(idev->cnf.disable_ipv6, newf);
 			if (changed)
 				dev_disable_change(idev);
 		}
···
 
 static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
 {
-	struct net *net;
+	struct net *net = (struct net *)table->extra2;
 	int old;
+
+	if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
+		WRITE_ONCE(*p, newf);
+		return 0;
+	}
 
 	if (!rtnl_trylock())
 		return restart_syscall();
 
-	net = (struct net *)table->extra2;
 	old = *p;
-	*p = newf;
-
-	if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
-		rtnl_unlock();
-		return 0;
-	}
+	WRITE_ONCE(*p, newf);
 
 	if (p == &net->ipv6.devconf_all->disable_ipv6) {
-		net->ipv6.devconf_dflt->disable_ipv6 = newf;
+		WRITE_ONCE(net->ipv6.devconf_dflt->disable_ipv6, newf);
 		addrconf_disable_change(net, newf);
 	} else if ((!newf) ^ (!old))
 		dev_disable_change((struct inet6_dev *)table->extra1);
···
 		} else if (&net->ipv6.devconf_all->addr_gen_mode == ctl->data) {
 			struct net_device *dev;
 
-			net->ipv6.devconf_dflt->addr_gen_mode = new_val;
+			WRITE_ONCE(net->ipv6.devconf_dflt->addr_gen_mode, new_val);
 			for_each_netdev(net, dev) {
 				idev = __in6_dev_get(dev);
 				if (idev &&
···
 			}
 		}
 
-		*((u32 *)ctl->data) = new_val;
+		WRITE_ONCE(*((u32 *)ctl->data), new_val);
 	}
 
 out:
···
 static
 int addrconf_disable_policy(struct ctl_table *ctl, int *valp, int val)
 {
+	struct net *net = (struct net *)ctl->extra2;
 	struct inet6_dev *idev;
-	struct net *net;
+
+	if (valp == &net->ipv6.devconf_dflt->disable_policy) {
+		WRITE_ONCE(*valp, val);
+		return 0;
+	}
 
 	if (!rtnl_trylock())
 		return restart_syscall();
 
-	*valp = val;
-
-	net = (struct net *)ctl->extra2;
-	if (valp == &net->ipv6.devconf_dflt->disable_policy) {
-		rtnl_unlock();
-		return 0;
-	}
+	WRITE_ONCE(*valp, val);
 
 	if (valp == &net->ipv6.devconf_all->disable_policy)  {
 		struct net_device *dev;
···
 	err = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETNETCONF,
 				   inet6_netconf_get_devconf,
 				   inet6_netconf_dump_devconf,
-				   RTNL_FLAG_DOIT_UNLOCKED);
+				   RTNL_FLAG_DOIT_UNLOCKED |
+				   RTNL_FLAG_DUMP_UNLOCKED);
 	if (err < 0)
 		goto errout;
 	err = ipv6_addr_label_rtnl_register();

net/ipv6/exthdrs.c

···
 
 	idev = __in6_dev_get(skb->dev);
 
-	accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
-	if (accept_seg6 > idev->cnf.seg6_enabled)
-		accept_seg6 = idev->cnf.seg6_enabled;
+	accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
+			  READ_ONCE(idev->cnf.seg6_enabled));
 
 	if (!accept_seg6) {
 		kfree_skb(skb);
···
 	struct ipv6_rt_hdr *hdr;
 	struct rt0_hdr *rthdr;
 	struct net *net = dev_net(skb->dev);
-	int accept_source_route = net->ipv6.devconf_all->accept_source_route;
+	int accept_source_route;
 
-	if (idev && accept_source_route > idev->cnf.accept_source_route)
-		accept_source_route = idev->cnf.accept_source_route;
+	accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
+
+	if (idev)
+		accept_source_route = min(accept_source_route,
+					  READ_ONCE(idev->cnf.accept_source_route));
 
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
···
 		goto drop;
 
 	/* Ignore if IOAM is not enabled on ingress */
-	if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
+	if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled))
 		goto ignore;
 
 	/* Truncated Option header */

net/ipv6/ioam6.c

···
 		if (!skb->dev)
 			raw16 = IOAM6_U16_UNAVAILABLE;
 		else
-			raw16 = (__force u16)__in6_dev_get(skb->dev)->cnf.ioam6_id;
+			raw16 = (__force u16)READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_id);
 
 		*(__be16 *)data = cpu_to_be16(raw16);
 		data += sizeof(__be16);
···
 		if (skb_dst(skb)->dev->flags & IFF_LOOPBACK)
 			raw16 = IOAM6_U16_UNAVAILABLE;
 		else
-			raw16 = (__force u16)__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id;
+			raw16 = (__force u16)READ_ONCE(__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id);
 
 		*(__be16 *)data = cpu_to_be16(raw16);
 		data += sizeof(__be16);
···
 		if (!skb->dev)
 			raw32 = IOAM6_U32_UNAVAILABLE;
 		else
-			raw32 = __in6_dev_get(skb->dev)->cnf.ioam6_id_wide;
+			raw32 = READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_id_wide);
 
 		*(__be32 *)data = cpu_to_be32(raw32);
 		data += sizeof(__be32);
···
 		if (skb_dst(skb)->dev->flags & IFF_LOOPBACK)
 			raw32 = IOAM6_U32_UNAVAILABLE;
 		else
-			raw32 = __in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id_wide;
+			raw32 = READ_ONCE(__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id_wide);
 
 		*(__be32 *)data = cpu_to_be32(raw32);
 		data += sizeof(__be32);

net/ipv6/ip6_input.c

···
 
 	SKB_DR_SET(reason, NOT_SPECIFIED);
 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
-	    !idev || unlikely(idev->cnf.disable_ipv6)) {
+	    !idev || unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
-		if (idev && unlikely(idev->cnf.disable_ipv6))
+		if (idev && unlikely(READ_ONCE(idev->cnf.disable_ipv6)))
 			SKB_DR_SET(reason, IPV6DISABLED);
 		goto drop;
 	}
···
 	if (!ipv6_addr_is_multicast(&hdr->daddr) &&
 	    (skb->pkt_type == PACKET_BROADCAST ||
 	     skb->pkt_type == PACKET_MULTICAST) &&
-	    idev->cnf.drop_unicast_in_l2_multicast) {
+	    READ_ONCE(idev->cnf.drop_unicast_in_l2_multicast)) {
 		SKB_DR_SET(reason, UNICAST_IN_L2_MULTICAST);
 		goto err;
 	}

net/ipv6/ip6_output.c

···
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->dev = dev;
 
-	if (unlikely(idev->cnf.disable_ipv6)) {
+	if (unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
 		IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
 		kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
 		return 0;
···
 	u32 mtu;
 
 	idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
-	if (net->ipv6.devconf_all->forwarding == 0)
+	if (READ_ONCE(net->ipv6.devconf_all->forwarding) == 0)
 		goto error;
 
 	if (skb->pkt_type != PACKET_HOST)
···
 	if (skb_warn_if_lro(skb))
 		goto drop;
 
-	if (!net->ipv6.devconf_all->disable_policy &&
-	    (!idev || !idev->cnf.disable_policy) &&
+	if (!READ_ONCE(net->ipv6.devconf_all->disable_policy) &&
+	    (!idev || !READ_ONCE(idev->cnf.disable_policy)) &&
 	    !xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 		goto drop;
···
 	}
 
 	/* XXX: idev->cnf.proxy_ndp? */
-	if (net->ipv6.devconf_all->proxy_ndp &&
+	if (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) &&
 	    pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 		int proxied = ip6_forward_proxy_check(skb);
 		if (proxied > 0) {

net/ipv6/ipv6_sockglue.c

···
 		}
 
 		if (val < 0)
-			val = sock_net(sk)->ipv6.devconf_all->hop_limit;
+			val = READ_ONCE(sock_net(sk)->ipv6.devconf_all->hop_limit);
 		break;
 	}
 

net/ipv6/mcast.c

···
 	int iv;
 
 	if (mld_in_v1_mode(idev))
-		iv = idev->cnf.mldv1_unsolicited_report_interval;
+		iv = READ_ONCE(idev->cnf.mldv1_unsolicited_report_interval);
 	else
-		iv = idev->cnf.mldv2_unsolicited_report_interval;
+		iv = READ_ONCE(idev->cnf.mldv2_unsolicited_report_interval);
 
 	return iv > 0 ? iv : 1;
 }
···
 
 static int mld_force_mld_version(const struct inet6_dev *idev)
 {
+	const struct net *net = dev_net(idev->dev);
+	int all_force;
+
+	all_force = READ_ONCE(net->ipv6.devconf_all->force_mld_version);
 	/* Normally, both are 0 here. If enforcement to a particular is
 	 * being used, individual device enforcement will have a lower
 	 * precedence over 'all' device (.../conf/all/force_mld_version).
 	 */
-
-	if (dev_net(idev->dev)->ipv6.devconf_all->force_mld_version != 0)
-		return dev_net(idev->dev)->ipv6.devconf_all->force_mld_version;
-	else
-		return idev->cnf.force_mld_version;
+	return all_force ?: READ_ONCE(idev->cnf.force_mld_version);
 }
 
 static bool mld_in_v2_mode_only(const struct inet6_dev *idev)

net/ipv6/ndisc.c

···
 
 	rcu_read_lock();
 	idev = __in6_dev_get(skb->dev);
-	tclass = idev ? idev->cnf.ndisc_tclass : 0;
+	tclass = idev ? READ_ONCE(idev->cnf.ndisc_tclass) : 0;
 	rcu_read_unlock();
 
 	skb_push(skb, sizeof(*hdr));
···
 		src_addr = solicited_addr;
 		if (ifp->flags & IFA_F_OPTIMISTIC)
 			override = false;
-		inc_opt |= ifp->idev->cnf.force_tllao;
+		inc_opt |= READ_ONCE(ifp->idev->cnf.force_tllao);
 		in6_ifa_put(ifp);
 	} else {
 		if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
···
 		}
 
 		if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
-		    (idev->cnf.forwarding &&
-		     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
+		    (READ_ONCE(idev->cnf.forwarding) &&
+		     (READ_ONCE(net->ipv6.devconf_all->proxy_ndp) ||
+		      READ_ONCE(idev->cnf.proxy_ndp)) &&
 		     (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
 			if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
 			    skb->pkt_type != PACKET_HOST &&
···
 	}
 
 	if (is_router < 0)
-		is_router = idev->cnf.forwarding;
+		is_router = READ_ONCE(idev->cnf.forwarding);
 
 	if (dad) {
 		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
···
 {
 	struct inet6_dev *idev = __in6_dev_get(dev);
 
-	switch (idev->cnf.accept_untracked_na) {
+	switch (READ_ONCE(idev->cnf.accept_untracked_na)) {
 	case 0: /* Don't accept untracked na (absent in neighbor cache) */
 		return 0;
 	case 1: /* Create new entries from na if currently untracked */
···
 	 * drop_unsolicited_na takes precedence over accept_untracked_na
 	 */
 	if (!msg->icmph.icmp6_solicited && idev &&
-	    idev->cnf.drop_unsolicited_na)
+	    READ_ONCE(idev->cnf.drop_unsolicited_na))
 		return reason;
 
 	if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
···
 	 * Note that we don't do a (daddr == all-routers-mcast) check.
 	 */
 	new_state = msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE;
-	if (!neigh && lladdr && idev && idev->cnf.forwarding) {
+	if (!neigh && lladdr && idev && READ_ONCE(idev->cnf.forwarding)) {
 		if (accept_untracked_na(dev, saddr)) {
 			neigh = neigh_create(&nd_tbl, &msg->target, dev);
 			new_state = NUD_STALE;
···
 		 * has already sent a NA to us.
 		 */
 		if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
-		    net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
+		    READ_ONCE(net->ipv6.devconf_all->forwarding) &&
+		    READ_ONCE(net->ipv6.devconf_all->proxy_ndp) &&
 		    pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
 			/* XXX: idev->cnf.proxy_ndp */
 			goto out;
···
 	}
 
 	/* Don't accept RS if we're not in router mode */
-	if (!idev->cnf.forwarding)
+	if (!READ_ONCE(idev->cnf.forwarding))
 		goto out;
 
 	/*
···
 	if (old_if_flags != in6_dev->if_flags)
 		send_ifinfo_notify = true;
 
-	if (!in6_dev->cnf.accept_ra_defrtr) {
+	if (!READ_ONCE(in6_dev->cnf.accept_ra_defrtr)) {
 		ND_PRINTK(2, info,
 			  "RA: %s, defrtr is false for dev: %s\n",
 			  __func__, skb->dev->name);
···
 	}
 
 	lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
-	if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_lft) {
+	if (lifetime != 0 &&
+	    lifetime < READ_ONCE(in6_dev->cnf.accept_ra_min_lft)) {
 		ND_PRINTK(2, info,
 			  "RA: router lifetime (%ds) is too short: %s\n",
 			  lifetime, skb->dev->name);
···
 	 * accept_ra_from_local is set to true.
 	 */
 	net = dev_net(in6_dev->dev);
-	if (!in6_dev->cnf.accept_ra_from_local &&
+	if (!READ_ONCE(in6_dev->cnf.accept_ra_from_local) &&
 	    ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
 		ND_PRINTK(2, info,
 			  "RA from local address detected on dev: %s: default router ignored\n",
···
 	pref = ra_msg->icmph.icmp6_router_pref;
 	/* 10b is handled as if it were 00b (medium) */
 	if (pref == ICMPV6_ROUTER_PREF_INVALID ||
-	    !in6_dev->cnf.accept_ra_rtr_pref)
+	    !READ_ONCE(in6_dev->cnf.accept_ra_rtr_pref))
 		pref = ICMPV6_ROUTER_PREF_MEDIUM;
 #endif
 	/* routes added from RAs do not use nexthop objects */
···
 
 		spin_unlock_bh(&table->tb6_lock);
 	}
-	if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
+	if (READ_ONCE(in6_dev->cnf.accept_ra_min_hop_limit) < 256 &&
 	    ra_msg->icmph.icmp6_hop_limit) {
-		if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
-			in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
+		if (READ_ONCE(in6_dev->cnf.accept_ra_min_hop_limit) <=
+		    ra_msg->icmph.icmp6_hop_limit) {
+			WRITE_ONCE(in6_dev->cnf.hop_limit,
+				   ra_msg->icmph.icmp6_hop_limit);
 			fib6_metric_set(rt, RTAX_HOPLIMIT,
 					ra_msg->icmph.icmp6_hop_limit);
 		} else {
···
 	}
 
 #ifdef CONFIG_IPV6_ROUTE_INFO
-	if (!in6_dev->cnf.accept_ra_from_local &&
+	if (!READ_ONCE(in6_dev->cnf.accept_ra_from_local) &&
 	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
 			  in6_dev->dev, 0)) {
 		ND_PRINTK(2, info,
···
 		goto skip_routeinfo;
 	}
 
-	if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
+	if (READ_ONCE(in6_dev->cnf.accept_ra_rtr_pref) && ndopts.nd_opts_ri) {
 		struct nd_opt_hdr *p;
 		for (p = ndopts.nd_opts_ri;
 		     p;
···
 				continue;
 #endif
 			if (ri->prefix_len == 0 &&
-			    !in6_dev->cnf.accept_ra_defrtr)
+			    !READ_ONCE(in6_dev->cnf.accept_ra_defrtr))
 				continue;
 			if (ri->lifetime != 0 &&
-			    ntohl(ri->lifetime) < in6_dev->cnf.accept_ra_min_lft)
+			    ntohl(ri->lifetime) < READ_ONCE(in6_dev->cnf.accept_ra_min_lft))
 				continue;
-			if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
+			if (ri->prefix_len < READ_ONCE(in6_dev->cnf.accept_ra_rt_info_min_plen))
 				continue;
-			if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
+			if (ri->prefix_len > READ_ONCE(in6_dev->cnf.accept_ra_rt_info_max_plen))
 				continue;
 			rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
 				      &ipv6_hdr(skb)->saddr);
···
 	}
 #endif
 
-	if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
+	if (READ_ONCE(in6_dev->cnf.accept_ra_pinfo) && ndopts.nd_opts_pi) {
 		struct nd_opt_hdr *p;
 		for (p = ndopts.nd_opts_pi;
 		     p;
···
 		}
 	}
 
-	if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
+	if (ndopts.nd_opts_mtu && READ_ONCE(in6_dev->cnf.accept_ra_mtu)) {
 		__be32 n;
 		u32 mtu;
 
···
 
 		if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
 			ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
-		} else if (in6_dev->cnf.mtu6 != mtu) {
-			in6_dev->cnf.mtu6 = mtu;
+		} else if (READ_ONCE(in6_dev->cnf.mtu6) != mtu) {
+			WRITE_ONCE(in6_dev->cnf.mtu6, mtu);
 			fib6_metric_set(rt, RTAX_MTU, mtu);
 			rt6_mtu_change(skb->dev, mtu);
 		}
···
 	if (!idev)
 		return true;
 	if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
-	    idev->cnf.suppress_frag_ndisc) {
+	    READ_ONCE(idev->cnf.suppress_frag_ndisc)) {
 		net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
 		return true;
 	}
···
 		idev = in6_dev_get(dev);
 		if (!idev)
 			break;
-		if (idev->cnf.ndisc_notify ||
-		    net->ipv6.devconf_all->ndisc_notify)
+		if (READ_ONCE(idev->cnf.ndisc_notify) ||
+		    READ_ONCE(net->ipv6.devconf_all->ndisc_notify))
 			ndisc_send_unsol_na(dev);
 		in6_dev_put(idev);
 		break;
···
 		if (!idev)
 			evict_nocarrier = true;
 		else {
-			evict_nocarrier = idev->cnf.ndisc_evict_nocarrier &&
-					  net->ipv6.devconf_all->ndisc_evict_nocarrier;
+			evict_nocarrier = READ_ONCE(idev->cnf.ndisc_evict_nocarrier) &&
+					  READ_ONCE(net->ipv6.devconf_all->ndisc_evict_nocarrier);
 			in6_dev_put(idev);
 		}
 

net/ipv6/netfilter/nf_reject_ipv6.c

···
 
 	skb_reserve(nskb, LL_MAX_HEADER);
 	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
-				     net->ipv6.devconf_all->hop_limit);
+				     READ_ONCE(net->ipv6.devconf_all->hop_limit));
 	nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
 	nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
 
···
 
 	skb_reserve(nskb, LL_MAX_HEADER);
 	nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
-				     net->ipv6.devconf_all->hop_limit);
+				     READ_ONCE(net->ipv6.devconf_all->hop_limit));
 
 	skb_reset_transport_header(nskb);
 	icmp6h = skb_put_zero(nskb, sizeof(struct icmp6hdr));

net/ipv6/output_core.c

···
 		rcu_read_lock();
 		idev = __in6_dev_get(dev);
 		if (idev)
-			hoplimit = idev->cnf.hop_limit;
+			hoplimit = READ_ONCE(idev->cnf.hop_limit);
 		else
-			hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
+			hoplimit = READ_ONCE(dev_net(dev)->ipv6.devconf_all->hop_limit);
 		rcu_read_unlock();
 	}
 	return hoplimit;

net/ipv6/route.c

···
 		write_lock_bh(&neigh->lock);
 		if (!(neigh->nud_state & NUD_VALID) &&
 		    time_after(jiffies,
-			       neigh->updated + idev->cnf.rtr_probe_interval)) {
+			       neigh->updated +
+			       READ_ONCE(idev->cnf.rtr_probe_interval))) {
 			work = kmalloc(sizeof(*work), GFP_ATOMIC);
 			if (work)
 				__neigh_set_probe_once(neigh);
 		}
 		write_unlock_bh(&neigh->lock);
 	} else if (time_after(jiffies, last_probe +
-				       idev->cnf.rtr_probe_interval)) {
+				       READ_ONCE(idev->cnf.rtr_probe_interval))) {
 		work = kmalloc(sizeof(*work), GFP_ATOMIC);
 	}
 
···
 
 		rcu_read_lock();
 		idev = __in6_dev_get(dev);
-		mtu = idev->cnf.mtu6;
+		mtu = READ_ONCE(idev->cnf.mtu6);
 		rcu_read_unlock();
 	}
 
···
 
 	strict |= flags & RT6_LOOKUP_F_IFACE;
 	strict |= flags & RT6_LOOKUP_F_IGNORE_LINKSTATE;
-	if (net->ipv6.devconf_all->forwarding == 0)
+	if (READ_ONCE(net->ipv6.devconf_all->forwarding) == 0)
 		strict |= RT6_LOOKUP_F_REACHABLE;
 
 	rcu_read_lock();
···
 
 		mtu = IPV6_MIN_MTU;
 		idev = __in6_dev_get(dev);
-		if (idev && idev->cnf.mtu6 > mtu)
-			mtu = idev->cnf.mtu6;
+		if (idev)
+			mtu = max_t(u32, mtu, READ_ONCE(idev->cnf.mtu6));
 	}
 
 	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);
···
 	in6_dev = __in6_dev_get(skb->dev);
 	if (!in6_dev)
 		return;
-	if (in6_dev->cnf.forwarding || !in6_dev->cnf.accept_redirects)
+	if (READ_ONCE(in6_dev->cnf.forwarding) ||
+	    !READ_ONCE(in6_dev->cnf.accept_redirects))
 		return;
 
 	/* RFC2461 8.1:
···
 		f6i->dst_nocount = true;
 
 		if (!anycast &&
-		    (net->ipv6.devconf_all->disable_policy ||
-		     idev->cnf.disable_policy))
+		    (READ_ONCE(net->ipv6.devconf_all->disable_policy) ||
+		     READ_ONCE(idev->cnf.disable_policy)))
 			f6i->dst_nopolicy = true;
 	}
 

net/ipv6/seg6_hmac.c

···
 	struct sr6_tlv_hmac *tlv;
 	struct ipv6_sr_hdr *srh;
 	struct inet6_dev *idev;
+	int require_hmac;
 
 	idev = __in6_dev_get(skb->dev);
 
···
 
 	tlv = seg6_get_tlv_hmac(srh);
 
+	require_hmac = READ_ONCE(idev->cnf.seg6_require_hmac);
 	/* mandatory check but no tlv */
-	if (idev->cnf.seg6_require_hmac > 0 && !tlv)
+	if (require_hmac > 0 && !tlv)
 		return false;
 
 	/* no check */
-	if (idev->cnf.seg6_require_hmac < 0)
+	if (require_hmac < 0)
 		return true;
 
 	/* check only if present */
-	if (idev->cnf.seg6_require_hmac == 0 && !tlv)
+	if (require_hmac == 0 && !tlv)
 		return true;
 
 	/* now, seg6_require_hmac >= 0 && tlv */

net/netfilter/nf_synproxy_core.c

···
 	skb_reset_network_header(skb);
 	iph = skb_put(skb, sizeof(*iph));
 	ip6_flow_hdr(iph, 0, 0);
-	iph->hop_limit	= net->ipv6.devconf_all->hop_limit;
+	iph->hop_limit	= READ_ONCE(net->ipv6.devconf_all->hop_limit);
 	iph->nexthdr	= IPPROTO_TCP;
 	iph->saddr	= *saddr;
 	iph->daddr	= *daddr;