Merge v6.17.3linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

8 files changed, 109 insertions, 97 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index f8a8e46286b8..52599584422b 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -104,7 +104,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 		rcu_read_lock();
 		rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
 		if (rt) {
-			dev = dst_dev(&rt->dst);
+			dev = dst_dev_rcu(&rt->dst);
 			netdev_hold(dev, &dev_tracker, GFP_ATOMIC);
 			ip6_rt_put(rt);
 		} else if (ishost) {
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 44550957fd4e..56c974cf75d1 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -209,7 +209,8 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 	 * this lookup should be more aggressive (not longer than timeout).
 	 */
 	dst = ip6_route_output(net, sk, fl6);
-	dev = dst_dev(dst);
+	rcu_read_lock();
+	dev = dst_dev_rcu(dst);
 	if (dst->error) {
 		IP6_INC_STATS(net, ip6_dst_idev(dst),
 			      IPSTATS_MIB_OUTNOROUTES);
@@ -224,14 +225,12 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type,
 		if (rt->rt6i_dst.plen < 128)
 			tmo >>= ((128 - rt->rt6i_dst.plen)>>5);
 
-		rcu_read_lock();
 		peer = inet_getpeer_v6(net->ipv6.peers, &fl6->daddr);
 		res = inet_peer_xrlim_allow(peer, tmo);
-		rcu_read_unlock();
 	}
+	rcu_read_unlock();
 	if (!res)
-		__ICMP6_INC_STATS(net, ip6_dst_idev(dst),
-				  ICMP6_MIB_RATELIMITHOST);
+		__ICMP6_INC_STATS(net, NULL, ICMP6_MIB_RATELIMITHOST);
 	else
 		icmp_global_consume(net);
 	dst_release(dst);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1e1410237b6e..9d64c13bab5e 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -60,7 +60,7 @@
 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct net_device *dev = dst_dev(dst);
+	struct net_device *dev = dst_dev_rcu(dst);
 	struct inet6_dev *idev = ip6_dst_idev(dst);
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 	const struct in6_addr *daddr, *nexthop;
@@ -70,15 +70,12 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
 
 	/* Be paranoid, rather than too clever. */
 	if (unlikely(hh_len > skb_headroom(skb)) && dev->header_ops) {
-		/* Make sure idev stays alive */
-		rcu_read_lock();
+		/* idev stays alive because we hold rcu_read_lock(). */
 		skb = skb_expand_head(skb, hh_len);
 		if (!skb) {
 			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
-			rcu_read_unlock();
 			return -ENOMEM;
 		}
-		rcu_read_unlock();
 	}
 
 	hdr = ipv6_hdr(skb);
@@ -123,7 +120,6 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
 
 	IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 
-	rcu_read_lock();
 	nexthop = rt6_nexthop(dst_rt6_info(dst), daddr);
 	neigh = __ipv6_neigh_lookup_noref(dev, nexthop);
 
@@ -131,7 +127,6 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
 		if (unlikely(!neigh))
 			neigh = __neigh_create(&nd_tbl, nexthop, dev, false);
 		if (IS_ERR(neigh)) {
-			rcu_read_unlock();
 			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
 			kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
 			return -EINVAL;
@@ -139,7 +134,6 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
 	}
 	sock_confirm_neigh(skb, neigh);
 	ret = neigh_output(neigh, skb, false);
-	rcu_read_unlock();
 	return ret;
 }
 
@@ -233,22 +227,29 @@ static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *s
 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct net_device *dev = dst_dev(dst), *indev = skb->dev;
-	struct inet6_dev *idev = ip6_dst_idev(dst);
+	struct net_device *dev, *indev = skb->dev;
+	struct inet6_dev *idev;
+	int ret;
 
 	skb->protocol = htons(ETH_P_IPV6);
+	rcu_read_lock();
+	dev = dst_dev_rcu(dst);
+	idev = ip6_dst_idev(dst);
 	skb->dev = dev;
 
 	if (unlikely(!idev || READ_ONCE(idev->cnf.disable_ipv6))) {
 		IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
+		rcu_read_unlock();
 		kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
 		return 0;
 	}
 
-	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
-			    net, sk, skb, indev, dev,
-			    ip6_finish_output,
-			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
+	ret = NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+			   net, sk, skb, indev, dev,
+			   ip6_finish_output,
+			   !(IP6CB(skb)->flags & IP6SKB_REROUTED));
+	rcu_read_unlock();
+	return ret;
 }
 EXPORT_SYMBOL(ip6_output);
 
@@ -268,35 +269,36 @@ bool ip6_autoflowlabel(struct net *net, const struct sock *sk)
 int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	     __u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority)
 {
-	struct net *net = sock_net(sk);
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	struct in6_addr *first_hop = &fl6->daddr;
 	struct dst_entry *dst = skb_dst(skb);
-	struct net_device *dev = dst_dev(dst);
 	struct inet6_dev *idev = ip6_dst_idev(dst);
 	struct hop_jumbo_hdr *hop_jumbo;
 	int hoplen = sizeof(*hop_jumbo);
+	struct net *net = sock_net(sk);
 	unsigned int head_room;
+	struct net_device *dev;
 	struct ipv6hdr *hdr;
 	u8  proto = fl6->flowi6_proto;
 	int seg_len = skb->len;
-	int hlimit = -1;
+	int ret, hlimit = -1;
 	u32 mtu;
 
+	rcu_read_lock();
+
+	dev = dst_dev_rcu(dst);
 	head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
 	if (opt)
 		head_room += opt->opt_nflen + opt->opt_flen;
 
 	if (unlikely(head_room > skb_headroom(skb))) {
-		/* Make sure idev stays alive */
-		rcu_read_lock();
+		/* idev stays alive while we hold rcu_read_lock(). */
 		skb = skb_expand_head(skb, head_room);
 		if (!skb) {
 			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
-			rcu_read_unlock();
-			return -ENOBUFS;
+			ret = -ENOBUFS;
+			goto unlock;
 		}
-		rcu_read_unlock();
 	}
 
 	if (opt) {
@@ -358,17 +360,21 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 		 * skb to its handler for processing
 		 */
 		skb = l3mdev_ip6_out((struct sock *)sk, skb);
-		if (unlikely(!skb))
-			return 0;
+		if (unlikely(!skb)) {
+			ret = 0;
+			goto unlock;
+		}
 
 		/* hooks should never assume socket lock is held.
 		 * we promote our socket to non const
 		 */
-		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
-			       net, (struct sock *)sk, skb, NULL, dev,
-			       dst_output);
+		ret = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+			      net, (struct sock *)sk, skb, NULL, dev,
+			      dst_output);
+		goto unlock;
 	}
 
+	ret = -EMSGSIZE;
 	skb->dev = dev;
 	/* ipv6_local_error() does not require socket lock,
 	 * we promote our socket to non const
@@ -377,7 +383,9 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 
 	IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
 	kfree_skb(skb);
-	return -EMSGSIZE;
+unlock:
+	rcu_read_unlock();
+	return ret;
 }
 EXPORT_SYMBOL(ip6_xmit);
 
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 36ca27496b3c..016b572e7d6f 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -169,6 +169,29 @@ static int unsolicited_report_interval(struct inet6_dev *idev)
 	return iv > 0 ? iv : 1;
 }
 
+static struct net_device *ip6_mc_find_dev(struct net *net,
+					  const struct in6_addr *group,
+					  int ifindex)
+{
+	struct net_device *dev = NULL;
+	struct rt6_info *rt;
+
+	if (ifindex == 0) {
+		rcu_read_lock();
+		rt = rt6_lookup(net, group, NULL, 0, NULL, 0);
+		if (rt) {
+			dev = dst_dev_rcu(&rt->dst);
+			dev_hold(dev);
+			ip6_rt_put(rt);
+		}
+		rcu_read_unlock();
+	} else {
+		dev = dev_get_by_index(net, ifindex);
+	}
+
+	return dev;
+}
+
 /*
  *	socket join on multicast group
  */
@@ -191,28 +214,13 @@ static int __ipv6_sock_mc_join(struct sock *sk, int ifindex,
 	}
 
 	mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL);
-
 	if (!mc_lst)
 		return -ENOMEM;
 
 	mc_lst->next = NULL;
 	mc_lst->addr = *addr;
 
-	if (ifindex == 0) {
-		struct rt6_info *rt;
-
-		rcu_read_lock();
-		rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
-		if (rt) {
-			dev = dst_dev(&rt->dst);
-			dev_hold(dev);
-			ip6_rt_put(rt);
-		}
-		rcu_read_unlock();
-	} else {
-		dev = dev_get_by_index(net, ifindex);
-	}
-
+	dev = ip6_mc_find_dev(net, addr, ifindex);
 	if (!dev) {
 		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
 		return -ENODEV;
@@ -302,27 +310,14 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 }
 EXPORT_SYMBOL(ipv6_sock_mc_drop);
 
-static struct inet6_dev *ip6_mc_find_dev(struct net *net,
-					 const struct in6_addr *group,
-					 int ifindex)
+static struct inet6_dev *ip6_mc_find_idev(struct net *net,
+					  const struct in6_addr *group,
+					  int ifindex)
 {
-	struct net_device *dev = NULL;
+	struct net_device *dev;
 	struct inet6_dev *idev;
 
-	if (ifindex == 0) {
-		struct rt6_info *rt;
-
-		rcu_read_lock();
-		rt = rt6_lookup(net, group, NULL, 0, NULL, 0);
-		if (rt) {
-			dev = dst_dev(&rt->dst);
-			dev_hold(dev);
-			ip6_rt_put(rt);
-		}
-		rcu_read_unlock();
-	} else {
-		dev = dev_get_by_index(net, ifindex);
-	}
+	dev = ip6_mc_find_dev(net, group, ifindex);
 	if (!dev)
 		return NULL;
 
@@ -374,7 +369,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 	if (!ipv6_addr_is_multicast(group))
 		return -EINVAL;
 
-	idev = ip6_mc_find_dev(net, group, pgsr->gsr_interface);
+	idev = ip6_mc_find_idev(net, group, pgsr->gsr_interface);
 	if (!idev)
 		return -ENODEV;
 
@@ -509,7 +504,7 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
 	    gsf->gf_fmode != MCAST_EXCLUDE)
 		return -EINVAL;
 
-	idev = ip6_mc_find_dev(net, group, gsf->gf_interface);
+	idev = ip6_mc_find_idev(net, group, gsf->gf_interface);
 	if (!idev)
 		return -ENODEV;
 
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 7d5abb3158ec..d6bb1e2f6192 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -505,7 +505,7 @@ void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr,
 
 	ip6_nd_hdr(skb, saddr, daddr, READ_ONCE(inet6_sk(sk)->hop_limit), skb->len);
 
-	dev = dst_dev(dst);
+	dev = dst_dev_rcu(dst);
 	idev = __in6_dev_get(dev);
 	IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
 
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index d21fe27fe21e..1c9b283a4132 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -104,18 +104,20 @@ EXPORT_SYMBOL(ip6_find_1stfragopt);
 int ip6_dst_hoplimit(struct dst_entry *dst)
 {
 	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
+
+	rcu_read_lock();
 	if (hoplimit == 0) {
-		struct net_device *dev = dst_dev(dst);
+		struct net_device *dev = dst_dev_rcu(dst);
 		struct inet6_dev *idev;
 
-		rcu_read_lock();
 		idev = __in6_dev_get(dev);
 		if (idev)
 			hoplimit = READ_ONCE(idev->cnf.hop_limit);
 		else
 			hoplimit = READ_ONCE(dev_net(dev)->ipv6.devconf_all->hop_limit);
-		rcu_read_unlock();
 	}
+	rcu_read_unlock();
+
 	return hoplimit;
 }
 EXPORT_SYMBOL(ip6_dst_hoplimit);
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index 752327b10dde..eb268b070025 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -85,7 +85,6 @@ static const struct snmp_mib snmp6_ipstats_list[] = {
 	SNMP_MIB_ITEM("Ip6InECT0Pkts", IPSTATS_MIB_ECT0PKTS),
 	SNMP_MIB_ITEM("Ip6InCEPkts", IPSTATS_MIB_CEPKTS),
 	SNMP_MIB_ITEM("Ip6OutTransmits", IPSTATS_MIB_OUTPKTS),
-	SNMP_MIB_SENTINEL
 };
 
 static const struct snmp_mib snmp6_icmp6_list[] = {
@@ -95,8 +94,8 @@ static const struct snmp_mib snmp6_icmp6_list[] = {
 	SNMP_MIB_ITEM("Icmp6OutMsgs", ICMP6_MIB_OUTMSGS),
 	SNMP_MIB_ITEM("Icmp6OutErrors", ICMP6_MIB_OUTERRORS),
 	SNMP_MIB_ITEM("Icmp6InCsumErrors", ICMP6_MIB_CSUMERRORS),
+/* ICMP6_MIB_RATELIMITHOST needs to be last, see snmp6_dev_seq_show(). */
 	SNMP_MIB_ITEM("Icmp6OutRateLimitHost", ICMP6_MIB_RATELIMITHOST),
-	SNMP_MIB_SENTINEL
 };
 
 /* RFC 4293 v6 ICMPMsgStatsTable; named items for RFC 2466 compatibility */
@@ -129,7 +128,6 @@ static const struct snmp_mib snmp6_udp6_list[] = {
 	SNMP_MIB_ITEM("Udp6InCsumErrors", UDP_MIB_CSUMERRORS),
 	SNMP_MIB_ITEM("Udp6IgnoredMulti", UDP_MIB_IGNOREDMULTI),
 	SNMP_MIB_ITEM("Udp6MemErrors", UDP_MIB_MEMERRORS),
-	SNMP_MIB_SENTINEL
 };
 
 static const struct snmp_mib snmp6_udplite6_list[] = {
@@ -141,7 +139,6 @@ static const struct snmp_mib snmp6_udplite6_list[] = {
 	SNMP_MIB_ITEM("UdpLite6SndbufErrors", UDP_MIB_SNDBUFERRORS),
 	SNMP_MIB_ITEM("UdpLite6InCsumErrors", UDP_MIB_CSUMERRORS),
 	SNMP_MIB_ITEM("UdpLite6MemErrors", UDP_MIB_MEMERRORS),
-	SNMP_MIB_SENTINEL
 };
 
 static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, atomic_long_t *smib)
@@ -182,35 +179,37 @@ static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, atomic_long_t *smib)
  */
 static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib,
 				atomic_long_t *smib,
-				const struct snmp_mib *itemlist)
+				const struct snmp_mib *itemlist,
+				int cnt)
 {
 	unsigned long buff[SNMP_MIB_MAX];
 	int i;
 
 	if (pcpumib) {
-		memset(buff, 0, sizeof(unsigned long) * SNMP_MIB_MAX);
+		memset(buff, 0, sizeof(unsigned long) * cnt);
 
-		snmp_get_cpu_field_batch(buff, itemlist, pcpumib);
-		for (i = 0; itemlist[i].name; i++)
+		snmp_get_cpu_field_batch_cnt(buff, itemlist, cnt, pcpumib);
+		for (i = 0; i < cnt; i++)
 			seq_printf(seq, "%-32s\t%lu\n",
 				   itemlist[i].name, buff[i]);
 	} else {
-		for (i = 0; itemlist[i].name; i++)
+		for (i = 0; i < cnt; i++)
 			seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name,
 				   atomic_long_read(smib + itemlist[i].entry));
 	}
 }
 
 static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib,
-				  const struct snmp_mib *itemlist, size_t syncpoff)
+				  const struct snmp_mib *itemlist,
+				  int cnt, size_t syncpoff)
 {
 	u64 buff64[SNMP_MIB_MAX];
 	int i;
 
-	memset(buff64, 0, sizeof(u64) * SNMP_MIB_MAX);
+	memset(buff64, 0, sizeof(u64) * cnt);
 
-	snmp_get_cpu_field64_batch(buff64, itemlist, mib, syncpoff);
-	for (i = 0; itemlist[i].name; i++)
+	snmp_get_cpu_field64_batch_cnt(buff64, itemlist, cnt, mib, syncpoff);
+	for (i = 0; i < cnt; i++)
 		seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name, buff64[i]);
 }
 
@@ -219,14 +218,19 @@ static int snmp6_seq_show(struct seq_file *seq, void *v)
 	struct net *net = (struct net *)seq->private;
 
 	snmp6_seq_show_item64(seq, net->mib.ipv6_statistics,
-			    snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
+			      snmp6_ipstats_list,
+			      ARRAY_SIZE(snmp6_ipstats_list),
+			      offsetof(struct ipstats_mib, syncp));
 	snmp6_seq_show_item(seq, net->mib.icmpv6_statistics,
-			    NULL, snmp6_icmp6_list);
+			    NULL, snmp6_icmp6_list,
+			    ARRAY_SIZE(snmp6_icmp6_list));
 	snmp6_seq_show_icmpv6msg(seq, net->mib.icmpv6msg_statistics->mibs);
 	snmp6_seq_show_item(seq, net->mib.udp_stats_in6,
-			    NULL, snmp6_udp6_list);
+			    NULL, snmp6_udp6_list,
+			    ARRAY_SIZE(snmp6_udp6_list));
 	snmp6_seq_show_item(seq, net->mib.udplite_stats_in6,
-			    NULL, snmp6_udplite6_list);
+			    NULL, snmp6_udplite6_list,
+			    ARRAY_SIZE(snmp6_udplite6_list));
 	return 0;
 }
 
@@ -236,9 +240,14 @@ static int snmp6_dev_seq_show(struct seq_file *seq, void *v)
 
 	seq_printf(seq, "%-32s\t%u\n", "ifIndex", idev->dev->ifindex);
 	snmp6_seq_show_item64(seq, idev->stats.ipv6,
-			    snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
+			      snmp6_ipstats_list,
+			      ARRAY_SIZE(snmp6_ipstats_list),
+			      offsetof(struct ipstats_mib, syncp));
+
+	/* Per idev icmp stats do not have ICMP6_MIB_RATELIMITHOST */
 	snmp6_seq_show_item(seq, NULL, idev->stats.icmpv6dev->mibs,
-			    snmp6_icmp6_list);
+			    snmp6_icmp6_list, ARRAY_SIZE(snmp6_icmp6_list) - 1);
+
 	snmp6_seq_show_icmpv6msg(seq, idev->stats.icmpv6msgdev->mibs);
 	return 0;
 }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3299cfa12e21..3371f16b7a3e 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2943,7 +2943,7 @@ static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
 
 		if (res.f6i->nh) {
 			struct fib6_nh_match_arg arg = {
-				.dev = dst_dev(dst),
+				.dev = dst_dev_rcu(dst),
 				.gw = &rt6->rt6i_gateway,
 			};
 
@@ -3238,7 +3238,6 @@ EXPORT_SYMBOL_GPL(ip6_sk_redirect);
 
 static unsigned int ip6_default_advmss(const struct dst_entry *dst)
 {
-	struct net_device *dev = dst_dev(dst);
 	unsigned int mtu = dst_mtu(dst);
 	struct net *net;
 
@@ -3246,7 +3245,7 @@ static unsigned int ip6_default_advmss(const struct dst_entry *dst)
 
 	rcu_read_lock();
 
-	net = dev_net_rcu(dev);
+	net = dst_dev_net_rcu(dst);
 	if (mtu < net->ipv6.sysctl.ip6_rt_min_advmss)
 		mtu = net->ipv6.sysctl.ip6_rt_min_advmss;
 
@@ -4301,7 +4300,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu
 
 	if (res.f6i->nh) {
 		struct fib6_nh_match_arg arg = {
-			.dev = dst_dev(dst),
+			.dev = dst_dev_rcu(dst),
 			.gw = &rt->rt6i_gateway,
 		};