[NETLINK]: Don't BUG on undersized allocations

Currently netlink users BUG when the allocated skb for an event
notification is undersized. While this is certainly a kernel bug,
its not critical and crashing the kernel is too drastic, especially
when considering that these errors have appeared multiple times in
the past and it BUGs even if no listeners are present.

This patch replaces BUG by WARN_ON and changes the notification
functions to inform potential listeners of undersized allocations
using a unique error code (EMSGSIZE).
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

@@ -45,7 +45,7 @@ static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *por
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	hdr = nlmsg_data(nlh);
 	hdr->ifi_family = AF_BRIDGE;
@@ -72,7 +72,8 @@ static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *por
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 /*
@@ -89,9 +90,12 @@ void br_ifinfo_notify(int event, struct net_bridge_port *port)
 		goto errout;
 
 	err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
-	/* failure implies BUG in br_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in br_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 errout:
 	if (err < 0)

net/core/fib_rules.c

@@ -331,7 +331,7 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
 	if (nlh == NULL)
-		return -1;
+		return -EMSGSIZE;
 
 	frh = nlmsg_data(nlh);
 	frh->table = rule->table;
@@ -359,7 +359,8 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family)
@@ -405,9 +406,12 @@ static void notify_rule_change(int event, struct fib_rule *rule,
 		goto errout;
 
 	err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
-	/* failure implies BUG in fib_rule_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL);
 errout:
 	if (err < 0)

net/core/neighbour.c

@@ -1637,7 +1637,7 @@ static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ndtmsg = nlmsg_data(nlh);
 
@@ -1706,7 +1706,8 @@ static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
 
 nla_put_failure:
 	read_unlock_bh(&tbl->lock);
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static int neightbl_fill_param_info(struct sk_buff *skb,
@@ -1720,7 +1721,7 @@ static int neightbl_fill_param_info(struct sk_buff *skb,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndtmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ndtmsg = nlmsg_data(nlh);
 
@@ -1737,7 +1738,8 @@ static int neightbl_fill_param_info(struct sk_buff *skb,
 	return nlmsg_end(skb, nlh);
 errout:
 	read_unlock_bh(&tbl->lock);
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
  
 static inline struct neigh_parms *lookup_neigh_params(struct neigh_table *tbl,
@@ -1955,7 +1957,7 @@ static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ndm = nlmsg_data(nlh);
 	ndm->ndm_family	 = neigh->ops->family;
@@ -1987,7 +1989,8 @@ static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 
@@ -2429,9 +2432,12 @@ static void __neigh_notify(struct neighbour *n, int type, int flags)
 		goto errout;
 
 	err = neigh_fill_info(skb, n, 0, 0, type, flags);
-	/* failure implies BUG in neigh_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in neigh_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
 errout:
 	if (err < 0)

net/core/rtnetlink.c

@@ -320,7 +320,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ifm = nlmsg_data(nlh);
 	ifm->ifi_family = AF_UNSPEC;
@@ -384,7 +384,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
@@ -633,9 +634,12 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
 
 	err = rtnl_fill_ifinfo(nskb, dev, iw, iw_buf_len, RTM_NEWLINK,
 			       NETLINK_CB(skb).pid, nlh->nlmsg_seq, 0, 0);
-	/* failure impilies BUG in if_nlmsg_size or wireless_rtnetlink_get */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in if_nlmsg_size */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(nskb);
+		goto errout;
+	}
 	err = rtnl_unicast(nskb, NETLINK_CB(skb).pid);
 errout:
 	kfree(iw_buf);
@@ -678,9 +682,12 @@ void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
 		goto errout;
 
 	err = rtnl_fill_ifinfo(skb, dev, NULL, 0, type, 0, 0, change, 0);
-	/* failure implies BUG in if_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in if_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_KERNEL);
 errout:
 	if (err < 0)

net/decnet/dn_dev.c

@@ -749,7 +749,7 @@ static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ifm = nlmsg_data(nlh);
 	ifm->ifa_family = AF_DECnet;
@@ -768,7 +768,8 @@ static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
@@ -781,9 +782,12 @@ static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
 		goto errout;
 
 	err = dn_nl_fill_ifaddr(skb, ifa, 0, 0, event, 0);
-	/* failure implies BUG in dn_ifaddr_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in dn_ifaddr_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
 errout:
 	if (err < 0)

net/decnet/dn_table.c

@@ -350,7 +350,7 @@ static int dn_fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 nlmsg_failure:
 rtattr_failure:
         skb_trim(skb, b - skb->data);
-        return -1;
+        return -EMSGSIZE;
 }
 
 
@@ -368,9 +368,12 @@ static void dn_rtmsg_fib(int event, struct dn_fib_node *f, int z, u32 tb_id,
         err = dn_fib_dump_info(skb, pid, nlh->nlmsg_seq, event, tb_id,
 			       f->fn_type, f->fn_scope, &f->fn_key, z,
 			       DN_FIB_INFO(f), 0);
-	/* failure implies BUG in dn_fib_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in dn_fib_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, pid, RTNLGRP_DECnet_ROUTE, nlh, GFP_KERNEL);
 errout:
 	if (err < 0)

net/ipv4/devinet.c

@@ -1140,7 +1140,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	ifm = nlmsg_data(nlh);
 	ifm->ifa_family = AF_INET;
@@ -1167,7 +1167,8 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static int inet_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
@@ -1225,9 +1226,12 @@ static void rtmsg_ifa(int event, struct in_ifaddr* ifa, struct nlmsghdr *nlh,
 		goto errout;
 
 	err = inet_fill_ifaddr(skb, ifa, pid, seq, event, 0);
-	/* failure implies BUG in inet_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, pid, RTNLGRP_IPV4_IFADDR, nlh, GFP_KERNEL);
 errout:
 	if (err < 0)

net/ipv4/fib_semantics.c

@@ -314,9 +314,12 @@ void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 	err = fib_dump_info(skb, info->pid, seq, event, tb_id,
 			    fa->fa_type, fa->fa_scope, key, dst_len,
 			    fa->fa_tos, fa->fa_info, 0);
-	/* failure implies BUG in fib_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in fib_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, info->pid, RTNLGRP_IPV4_ROUTE,
 			  info->nlh, GFP_KERNEL);
 errout:
@@ -960,7 +963,7 @@ int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	rtm = nlmsg_data(nlh);
 	rtm->rtm_family = AF_INET;
@@ -1031,7 +1034,8 @@ int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 /*

net/ipv4/inet_diag.c

@@ -153,7 +153,7 @@ static int inet_csk_diag_fill(struct sock *sk,
 rtattr_failure:
 nlmsg_failure:
 	skb_trim(skb, b - skb->data);
-	return -1;
+	return -EMSGSIZE;
 }
 
 static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
@@ -209,7 +209,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
 	return skb->len;
 nlmsg_failure:
 	skb_trim(skb, previous_tail - skb->data);
-	return -1;
+	return -EMSGSIZE;
 }
 
 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
@@ -274,11 +274,14 @@ static int inet_diag_get_exact(struct sk_buff *in_skb,
 	if (!rep)
 		goto out;
 
-	if (sk_diag_fill(sk, rep, req->idiag_ext,
+	err = sk_diag_fill(sk, rep, req->idiag_ext,
 			   NETLINK_CB(in_skb).pid,
-			 nlh->nlmsg_seq, 0, nlh) <= 0)
-		BUG();
-
+			   nlh->nlmsg_seq, 0, nlh);
+	if (err < 0) {
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(rep);
+		goto out;
+	}
 	err = netlink_unicast(idiagnl, rep, NETLINK_CB(in_skb).pid,
 			      MSG_DONTWAIT);
 	if (err > 0)

net/ipv4/route.c

@@ -2635,7 +2635,7 @@ static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	r = nlmsg_data(nlh);
 	r->rtm_family	 = AF_INET;
@@ -2718,7 +2718,8 @@ static int rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr* nlh, void *arg)

net/ipv6/addrconf.c

@@ -3117,7 +3117,7 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(struct ifaddrmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	put_ifaddrmsg(nlh, ifa->prefix_len, ifa->flags, rt_scope(ifa->scope),
 		      ifa->idev->dev->ifindex);
@@ -3137,8 +3137,10 @@ static int inet6_fill_ifaddr(struct sk_buff *skb, struct inet6_ifaddr *ifa,
 	}
 
 	if (nla_put(skb, IFA_ADDRESS, 16, &ifa->addr) < 0 ||
-	    put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0)
-		return nlmsg_cancel(skb, nlh);
+	    put_cacheinfo(skb, ifa->cstamp, ifa->tstamp, preferred, valid) < 0) {
+		nlmsg_cancel(skb, nlh);
+		return -EMSGSIZE;
+	}
 
 	return nlmsg_end(skb, nlh);
 }
@@ -3155,13 +3157,15 @@ static int inet6_fill_ifmcaddr(struct sk_buff *skb, struct ifmcaddr6 *ifmca,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(struct ifaddrmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
 	if (nla_put(skb, IFA_MULTICAST, 16, &ifmca->mca_addr) < 0 ||
 	    put_cacheinfo(skb, ifmca->mca_cstamp, ifmca->mca_tstamp,
-			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0)
-		return nlmsg_cancel(skb, nlh);
+			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
+		nlmsg_cancel(skb, nlh);
+		return -EMSGSIZE;
+	}
 
 	return nlmsg_end(skb, nlh);
 }
@@ -3178,13 +3182,15 @@ static int inet6_fill_ifacaddr(struct sk_buff *skb, struct ifacaddr6 *ifaca,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(struct ifaddrmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	put_ifaddrmsg(nlh, 128, IFA_F_PERMANENT, scope, ifindex);
 	if (nla_put(skb, IFA_ANYCAST, 16, &ifaca->aca_addr) < 0 ||
 	    put_cacheinfo(skb, ifaca->aca_cstamp, ifaca->aca_tstamp,
-			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0)
-		return nlmsg_cancel(skb, nlh);
+			  INFINITY_LIFE_TIME, INFINITY_LIFE_TIME) < 0) {
+		nlmsg_cancel(skb, nlh);
+		return -EMSGSIZE;
+	}
 
 	return nlmsg_end(skb, nlh);
 }
@@ -3334,9 +3340,12 @@ static int inet6_rtm_getaddr(struct sk_buff *in_skb, struct nlmsghdr* nlh,
 
 	err = inet6_fill_ifaddr(skb, ifa, NETLINK_CB(in_skb).pid,
 				nlh->nlmsg_seq, RTM_NEWADDR, 0);
-	/* failure implies BUG in inet6_ifaddr_msgsize() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout_ifa;
+	}
 	err = rtnl_unicast(skb, NETLINK_CB(in_skb).pid);
 errout_ifa:
 	in6_ifa_put(ifa);
@@ -3354,9 +3363,12 @@ static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa)
 		goto errout;
 
 	err = inet6_fill_ifaddr(skb, ifa, 0, 0, event, 0);
-	/* failure implies BUG in inet6_ifaddr_msgsize() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet6_ifaddr_msgsize() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_IPV6_IFADDR, NULL, GFP_ATOMIC);
 errout:
 	if (err < 0)
@@ -3426,7 +3438,7 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	hdr = nlmsg_data(nlh);
 	hdr->ifi_family = AF_INET6;
@@ -3469,7 +3481,8 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static int inet6_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
@@ -3507,9 +3520,12 @@ void inet6_ifinfo_notify(int event, struct inet6_dev *idev)
 		goto errout;
 
 	err = inet6_fill_ifinfo(skb, idev, 0, 0, event, 0);
-	/* failure implies BUG in inet6_if_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet6_if_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_IPV6_IFADDR, NULL, GFP_ATOMIC);
 errout:
 	if (err < 0)
@@ -3533,7 +3549,7 @@ static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev,
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*pmsg), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	pmsg = nlmsg_data(nlh);
 	pmsg->prefix_family = AF_INET6;
@@ -3558,7 +3574,8 @@ static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 static void inet6_prefix_notify(int event, struct inet6_dev *idev, 
@@ -3572,9 +3589,12 @@ static void inet6_prefix_notify(int event, struct inet6_dev *idev,
 		goto errout;
 
 	err = inet6_fill_prefix(skb, idev, pinfo, 0, 0, event, 0);
-	/* failure implies BUG in inet6_prefix_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in inet6_prefix_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, 0, RTNLGRP_IPV6_PREFIX, NULL, GFP_ATOMIC);
 errout:
 	if (err < 0)

net/ipv6/route.c

@@ -2040,7 +2040,7 @@ static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
 
 	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*rtm), flags);
 	if (nlh == NULL)
-		return -ENOBUFS;
+		return -EMSGSIZE;
 
 	rtm = nlmsg_data(nlh);
 	rtm->rtm_family = AF_INET6;
@@ -2111,7 +2111,8 @@ static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
 	return nlmsg_end(skb, nlh);
 
 nla_put_failure:
-	return nlmsg_cancel(skb, nlh);
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
 }
 
 int rt6_dump_route(struct rt6_info *rt, void *p_arg)
@@ -2222,9 +2223,12 @@ void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info)
 		goto errout;
 
 	err = rt6_fill_node(skb, rt, NULL, NULL, 0, event, pid, seq, 0, 0);
-	/* failure implies BUG in rt6_nlmsg_size() */
-	BUG_ON(err < 0);
-
+	if (err < 0) {
+		/* -EMSGSIZE implies BUG in rt6_nlmsg_size() */
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
 	err = rtnl_notify(skb, pid, RTNLGRP_IPV6_ROUTE, nlh, gfp_any());
 errout:
 	if (err < 0)