Patchwork [1/1] netfilter: ipset: Increase the number of maximal sets automatically

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Submitter Jozsef Kadlecsik
Date Nov. 27, 2012, 7:58 p.m.
Message ID <1354046289-17547-2-git-send-email-kadlec@blackhole.kfki.hu>
Download mbox | patch
Permalink /patch/202289/
State Accepted
Headers show

Comments

Jozsef Kadlecsik - Nov. 27, 2012, 7:58 p.m.
The max number of sets was hardcoded at kernel cofiguration time and
could only be modified via a module parameter. The patch adds the support
of increasing the max number of sets automatically, as needed.

The absolute limit for the maximal number of sets is 65534.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
---
 net/netfilter/ipset/ip_set_core.c |  243 ++++++++++++++++++++++++-------------
 1 files changed, 160 insertions(+), 83 deletions(-)
Pablo Neira - Dec. 3, 2012, 6:27 p.m.
On Tue, Nov 27, 2012 at 08:58:09PM +0100, Jozsef Kadlecsik wrote:
> The max number of sets was hardcoded at kernel cofiguration time and
> could only be modified via a module parameter. The patch adds the support
> of increasing the max number of sets automatically, as needed.
> 
> The absolute limit for the maximal number of sets is 65534.

Applied, thanks Jozsef.
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Patch

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 778465f..9c9db08 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -28,9 +28,10 @@  static LIST_HEAD(ip_set_type_list);		/* all registered set types */
 static DEFINE_MUTEX(ip_set_type_mutex);		/* protects ip_set_type_list */
 static DEFINE_RWLOCK(ip_set_ref_lock);		/* protects the set refs */
 
-static struct ip_set **ip_set_list;		/* all individual sets */
+static struct ip_set * __rcu *ip_set_list;	/* all individual sets */
 static ip_set_id_t ip_set_max = CONFIG_IP_SET_MAX; /* max number of sets */
 
+#define IP_SET_INC	64
 #define STREQ(a, b)	(strncmp(a, b, IPSET_MAXNAMELEN) == 0)
 
 static unsigned int max_sets;
@@ -42,6 +43,12 @@  MODULE_AUTHOR("Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>");
 MODULE_DESCRIPTION("core IP set support");
 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_IPSET);
 
+/* When the nfnl mutex is held: */
+#define nfnl_dereference(p)		\
+	rcu_dereference_protected(p, 1)
+#define nfnl_set(id)			\
+	nfnl_dereference(ip_set_list)[id]
+
 /*
  * The set types are implemented in modules and registered set types
  * can be found in ip_set_type_list. Adding/deleting types is
@@ -321,19 +328,19 @@  EXPORT_SYMBOL_GPL(ip_set_get_ipaddr6);
  */
 
 static inline void
-__ip_set_get(ip_set_id_t index)
+__ip_set_get(struct ip_set *set)
 {
 	write_lock_bh(&ip_set_ref_lock);
-	ip_set_list[index]->ref++;
+	set->ref++;
 	write_unlock_bh(&ip_set_ref_lock);
 }
 
 static inline void
-__ip_set_put(ip_set_id_t index)
+__ip_set_put(struct ip_set *set)
 {
 	write_lock_bh(&ip_set_ref_lock);
-	BUG_ON(ip_set_list[index]->ref == 0);
-	ip_set_list[index]->ref--;
+	BUG_ON(set->ref == 0);
+	set->ref--;
 	write_unlock_bh(&ip_set_ref_lock);
 }
 
@@ -344,12 +351,25 @@  __ip_set_put(ip_set_id_t index)
  * so it can't be destroyed (or changed) under our foot.
  */
 
+static inline struct ip_set *
+ip_set_rcu_get(ip_set_id_t index)
+{
+	struct ip_set *set;
+
+	rcu_read_lock();
+	/* ip_set_list itself needs to be protected */
+	set = rcu_dereference(ip_set_list)[index];
+	rcu_read_unlock();
+
+	return set;
+}
+
 int
 ip_set_test(ip_set_id_t index, const struct sk_buff *skb,
 	    const struct xt_action_param *par,
 	    const struct ip_set_adt_opt *opt)
 {
-	struct ip_set *set = ip_set_list[index];
+	struct ip_set *set = ip_set_rcu_get(index);
 	int ret = 0;
 
 	BUG_ON(set == NULL);
@@ -388,7 +408,7 @@  ip_set_add(ip_set_id_t index, const struct sk_buff *skb,
 	   const struct xt_action_param *par,
 	   const struct ip_set_adt_opt *opt)
 {
-	struct ip_set *set = ip_set_list[index];
+	struct ip_set *set = ip_set_rcu_get(index);
 	int ret;
 
 	BUG_ON(set == NULL);
@@ -411,7 +431,7 @@  ip_set_del(ip_set_id_t index, const struct sk_buff *skb,
 	   const struct xt_action_param *par,
 	   const struct ip_set_adt_opt *opt)
 {
-	struct ip_set *set = ip_set_list[index];
+	struct ip_set *set = ip_set_rcu_get(index);
 	int ret = 0;
 
 	BUG_ON(set == NULL);
@@ -440,14 +460,17 @@  ip_set_get_byname(const char *name, struct ip_set **set)
 	ip_set_id_t i, index = IPSET_INVALID_ID;
 	struct ip_set *s;
 
+	rcu_read_lock();
 	for (i = 0; i < ip_set_max; i++) {
-		s = ip_set_list[i];
+		s = rcu_dereference(ip_set_list)[i];
 		if (s != NULL && STREQ(s->name, name)) {
-			__ip_set_get(i);
+			__ip_set_get(s);
 			index = i;
 			*set = s;
+			break;
 		}
 	}
+	rcu_read_unlock();
 
 	return index;
 }
@@ -462,8 +485,13 @@  EXPORT_SYMBOL_GPL(ip_set_get_byname);
 void
 ip_set_put_byindex(ip_set_id_t index)
 {
-	if (ip_set_list[index] != NULL)
-		__ip_set_put(index);
+	struct ip_set *set;
+
+	rcu_read_lock();
+	set = rcu_dereference(ip_set_list)[index];
+	if (set != NULL)
+		__ip_set_put(set);
+	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(ip_set_put_byindex);
 
@@ -477,7 +505,7 @@  EXPORT_SYMBOL_GPL(ip_set_put_byindex);
 const char *
 ip_set_name_byindex(ip_set_id_t index)
 {
-	const struct ip_set *set = ip_set_list[index];
+	const struct ip_set *set = ip_set_rcu_get(index);
 
 	BUG_ON(set == NULL);
 	BUG_ON(set->ref == 0);
@@ -501,11 +529,18 @@  EXPORT_SYMBOL_GPL(ip_set_name_byindex);
 ip_set_id_t
 ip_set_nfnl_get(const char *name)
 {
+	ip_set_id_t i, index = IPSET_INVALID_ID;
 	struct ip_set *s;
-	ip_set_id_t index;
 
 	nfnl_lock();
-	index = ip_set_get_byname(name, &s);
+	for (i = 0; i < ip_set_max; i++) {
+		s = nfnl_set(i);
+		if (s != NULL && STREQ(s->name, name)) {
+			__ip_set_get(s);
+			index = i;
+			break;
+		}
+	}
 	nfnl_unlock();
 
 	return index;
@@ -521,12 +556,15 @@  EXPORT_SYMBOL_GPL(ip_set_nfnl_get);
 ip_set_id_t
 ip_set_nfnl_get_byindex(ip_set_id_t index)
 {
+	struct ip_set *set;
+
 	if (index > ip_set_max)
 		return IPSET_INVALID_ID;
 
 	nfnl_lock();
-	if (ip_set_list[index])
-		__ip_set_get(index);
+	set = nfnl_set(index);
+	if (set)
+		__ip_set_get(set);
 	else
 		index = IPSET_INVALID_ID;
 	nfnl_unlock();
@@ -545,8 +583,11 @@  EXPORT_SYMBOL_GPL(ip_set_nfnl_get_byindex);
 void
 ip_set_nfnl_put(ip_set_id_t index)
 {
+	struct ip_set *set;
 	nfnl_lock();
-	ip_set_put_byindex(index);
+	set = nfnl_set(index);
+	if (set != NULL)
+		__ip_set_put(set);
 	nfnl_unlock();
 }
 EXPORT_SYMBOL_GPL(ip_set_nfnl_put);
@@ -603,41 +644,46 @@  static const struct nla_policy ip_set_create_policy[IPSET_ATTR_CMD_MAX + 1] = {
 	[IPSET_ATTR_DATA]	= { .type = NLA_NESTED },
 };
 
-static ip_set_id_t
-find_set_id(const char *name)
+static struct ip_set *
+find_set_and_id(const char *name, ip_set_id_t *id)
 {
-	ip_set_id_t i, index = IPSET_INVALID_ID;
-	const struct ip_set *set;
+	struct ip_set *set = NULL;
+	ip_set_id_t i;
 
-	for (i = 0; index == IPSET_INVALID_ID && i < ip_set_max; i++) {
-		set = ip_set_list[i];
-		if (set != NULL && STREQ(set->name, name))
-			index = i;
+	*id = IPSET_INVALID_ID;
+	for (i = 0; i < ip_set_max; i++) {
+		set = nfnl_set(i);
+		if (set != NULL && STREQ(set->name, name)) {
+			*id = i;
+			break;
+		}
 	}
-	return index;
+	return (*id == IPSET_INVALID_ID ? NULL : set);
 }
 
 static inline struct ip_set *
 find_set(const char *name)
 {
-	ip_set_id_t index = find_set_id(name);
+	ip_set_id_t id;
 
-	return index == IPSET_INVALID_ID ? NULL : ip_set_list[index];
+	return find_set_and_id(name, &id);
 }
 
 static int
 find_free_id(const char *name, ip_set_id_t *index, struct ip_set **set)
 {
+	struct ip_set *s;
 	ip_set_id_t i;
 
 	*index = IPSET_INVALID_ID;
 	for (i = 0;  i < ip_set_max; i++) {
-		if (ip_set_list[i] == NULL) {
+		s = nfnl_set(i);
+		if (s == NULL) {
 			if (*index == IPSET_INVALID_ID)
 				*index = i;
-		} else if (STREQ(name, ip_set_list[i]->name)) {
+		} else if (STREQ(name, s->name)) {
 			/* Name clash */
-			*set = ip_set_list[i];
+			*set = s;
 			return -EEXIST;
 		}
 	}
@@ -730,10 +776,9 @@  ip_set_create(struct sock *ctnl, struct sk_buff *skb,
 	 * and check clashing.
 	 */
 	ret = find_free_id(set->name, &index, &clash);
-	if (ret != 0) {
+	if (ret == -EEXIST) {
 		/* If this is the same set and requested, ignore error */
-		if (ret == -EEXIST &&
-		    (flags & IPSET_FLAG_EXIST) &&
+		if ((flags & IPSET_FLAG_EXIST) &&
 		    STREQ(set->type->name, clash->type->name) &&
 		    set->type->family == clash->type->family &&
 		    set->type->revision_min == clash->type->revision_min &&
@@ -741,13 +786,36 @@  ip_set_create(struct sock *ctnl, struct sk_buff *skb,
 		    set->variant->same_set(set, clash))
 			ret = 0;
 		goto cleanup;
-	}
+	} else if (ret == -IPSET_ERR_MAX_SETS) {
+		struct ip_set **list, **tmp;
+		ip_set_id_t i = ip_set_max + IP_SET_INC;
+
+		if (i < ip_set_max || i == IPSET_INVALID_ID)
+			/* Wraparound */
+			goto cleanup;
+
+		list = kzalloc(sizeof(struct ip_set *) * i, GFP_KERNEL);
+		if (!list)
+			goto cleanup;
+		/* nfnl mutex is held, both lists are valid */
+		tmp = nfnl_dereference(ip_set_list);
+		memcpy(list, tmp, sizeof(struct ip_set *) * ip_set_max);
+		rcu_assign_pointer(ip_set_list, list);
+		/* Make sure all current packets have passed through */
+		synchronize_net();
+		/* Use new list */
+		index = ip_set_max;
+		ip_set_max = i;
+		kfree(tmp);
+		ret = 0;
+	} else if (ret)
+		goto cleanup;
 
 	/*
 	 * Finally! Add our shiny new set to the list, and be done.
 	 */
 	pr_debug("create: '%s' created with index %u!\n", set->name, index);
-	ip_set_list[index] = set;
+	nfnl_set(index) = set;
 
 	return ret;
 
@@ -772,10 +840,10 @@  ip_set_setname_policy[IPSET_ATTR_CMD_MAX + 1] = {
 static void
 ip_set_destroy_set(ip_set_id_t index)
 {
-	struct ip_set *set = ip_set_list[index];
+	struct ip_set *set = nfnl_set(index);
 
 	pr_debug("set: %s\n",  set->name);
-	ip_set_list[index] = NULL;
+	nfnl_set(index) = NULL;
 
 	/* Must call it without holding any lock */
 	set->variant->destroy(set);
@@ -788,6 +856,7 @@  ip_set_destroy(struct sock *ctnl, struct sk_buff *skb,
 	       const struct nlmsghdr *nlh,
 	       const struct nlattr * const attr[])
 {
+	struct ip_set *s;
 	ip_set_id_t i;
 	int ret = 0;
 
@@ -807,22 +876,24 @@  ip_set_destroy(struct sock *ctnl, struct sk_buff *skb,
 	read_lock_bh(&ip_set_ref_lock);
 	if (!attr[IPSET_ATTR_SETNAME]) {
 		for (i = 0; i < ip_set_max; i++) {
-			if (ip_set_list[i] != NULL && ip_set_list[i]->ref) {
+			s = nfnl_set(i);
+			if (s != NULL && s->ref) {
 				ret = -IPSET_ERR_BUSY;
 				goto out;
 			}
 		}
 		read_unlock_bh(&ip_set_ref_lock);
 		for (i = 0; i < ip_set_max; i++) {
-			if (ip_set_list[i] != NULL)
+			s = nfnl_set(i);
+			if (s != NULL)
 				ip_set_destroy_set(i);
 		}
 	} else {
-		i = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME]));
-		if (i == IPSET_INVALID_ID) {
+		s = find_set_and_id(nla_data(attr[IPSET_ATTR_SETNAME]), &i);
+		if (s == NULL) {
 			ret = -ENOENT;
 			goto out;
-		} else if (ip_set_list[i]->ref) {
+		} else if (s->ref) {
 			ret = -IPSET_ERR_BUSY;
 			goto out;
 		}
@@ -853,21 +924,24 @@  ip_set_flush(struct sock *ctnl, struct sk_buff *skb,
 	     const struct nlmsghdr *nlh,
 	     const struct nlattr * const attr[])
 {
+	struct ip_set *s;
 	ip_set_id_t i;
 
 	if (unlikely(protocol_failed(attr)))
 		return -IPSET_ERR_PROTOCOL;
 
 	if (!attr[IPSET_ATTR_SETNAME]) {
-		for (i = 0; i < ip_set_max; i++)
-			if (ip_set_list[i] != NULL)
-				ip_set_flush_set(ip_set_list[i]);
+		for (i = 0; i < ip_set_max; i++) {
+			s = nfnl_set(i);
+			if (s != NULL)
+				ip_set_flush_set(s);
+		}
 	} else {
-		i = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME]));
-		if (i == IPSET_INVALID_ID)
+		s = find_set(nla_data(attr[IPSET_ATTR_SETNAME]));
+		if (s == NULL)
 			return -ENOENT;
 
-		ip_set_flush_set(ip_set_list[i]);
+		ip_set_flush_set(s);
 	}
 
 	return 0;
@@ -889,7 +963,7 @@  ip_set_rename(struct sock *ctnl, struct sk_buff *skb,
 	      const struct nlmsghdr *nlh,
 	      const struct nlattr * const attr[])
 {
-	struct ip_set *set;
+	struct ip_set *set, *s;
 	const char *name2;
 	ip_set_id_t i;
 	int ret = 0;
@@ -911,8 +985,8 @@  ip_set_rename(struct sock *ctnl, struct sk_buff *skb,
 
 	name2 = nla_data(attr[IPSET_ATTR_SETNAME2]);
 	for (i = 0; i < ip_set_max; i++) {
-		if (ip_set_list[i] != NULL &&
-		    STREQ(ip_set_list[i]->name, name2)) {
+		s = nfnl_set(i);
+		if (s != NULL && STREQ(s->name, name2)) {
 			ret = -IPSET_ERR_EXIST_SETNAME2;
 			goto out;
 		}
@@ -947,17 +1021,14 @@  ip_set_swap(struct sock *ctnl, struct sk_buff *skb,
 		     attr[IPSET_ATTR_SETNAME2] == NULL))
 		return -IPSET_ERR_PROTOCOL;
 
-	from_id = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME]));
-	if (from_id == IPSET_INVALID_ID)
+	from = find_set_and_id(nla_data(attr[IPSET_ATTR_SETNAME]), &from_id);
+	if (from == NULL)
 		return -ENOENT;
 
-	to_id = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME2]));
-	if (to_id == IPSET_INVALID_ID)
+	to = find_set_and_id(nla_data(attr[IPSET_ATTR_SETNAME2]), &to_id);
+	if (to == NULL)
 		return -IPSET_ERR_EXIST_SETNAME2;
 
-	from = ip_set_list[from_id];
-	to = ip_set_list[to_id];
-
 	/* Features must not change.
 	 * Not an artificial restriction anymore, as we must prevent
 	 * possible loops created by swapping in setlist type of sets. */
@@ -971,8 +1042,8 @@  ip_set_swap(struct sock *ctnl, struct sk_buff *skb,
 
 	write_lock_bh(&ip_set_ref_lock);
 	swap(from->ref, to->ref);
-	ip_set_list[from_id] = to;
-	ip_set_list[to_id] = from;
+	nfnl_set(from_id) = to;
+	nfnl_set(to_id) = from;
 	write_unlock_bh(&ip_set_ref_lock);
 
 	return 0;
@@ -992,7 +1063,7 @@  static int
 ip_set_dump_done(struct netlink_callback *cb)
 {
 	if (cb->args[2]) {
-		pr_debug("release set %s\n", ip_set_list[cb->args[1]]->name);
+		pr_debug("release set %s\n", nfnl_set(cb->args[1])->name);
 		ip_set_put_byindex((ip_set_id_t) cb->args[1]);
 	}
 	return 0;
@@ -1030,8 +1101,11 @@  dump_init(struct netlink_callback *cb)
 	 */
 
 	if (cda[IPSET_ATTR_SETNAME]) {
-		index = find_set_id(nla_data(cda[IPSET_ATTR_SETNAME]));
-		if (index == IPSET_INVALID_ID)
+		struct ip_set *set;
+
+		set = find_set_and_id(nla_data(cda[IPSET_ATTR_SETNAME]),
+				      &index);
+		if (set == NULL)
 			return -ENOENT;
 
 		dump_type = DUMP_ONE;
@@ -1081,7 +1155,7 @@  dump_last:
 		 dump_type, dump_flags, cb->args[1]);
 	for (; cb->args[1] < max; cb->args[1]++) {
 		index = (ip_set_id_t) cb->args[1];
-		set = ip_set_list[index];
+		set = nfnl_set(index);
 		if (set == NULL) {
 			if (dump_type == DUMP_ONE) {
 				ret = -ENOENT;
@@ -1100,7 +1174,7 @@  dump_last:
 		if (!cb->args[2]) {
 			/* Start listing: make sure set won't be destroyed */
 			pr_debug("reference set\n");
-			__ip_set_get(index);
+			__ip_set_get(set);
 		}
 		nlh = start_msg(skb, NETLINK_CB(cb->skb).portid,
 				cb->nlh->nlmsg_seq, flags,
@@ -1159,7 +1233,7 @@  next_set:
 release_refcount:
 	/* If there was an error or set is done, release set */
 	if (ret || !cb->args[2]) {
-		pr_debug("release set %s\n", ip_set_list[index]->name);
+		pr_debug("release set %s\n", nfnl_set(index)->name);
 		ip_set_put_byindex(index);
 		cb->args[2] = 0;
 	}
@@ -1409,17 +1483,15 @@  ip_set_header(struct sock *ctnl, struct sk_buff *skb,
 	const struct ip_set *set;
 	struct sk_buff *skb2;
 	struct nlmsghdr *nlh2;
-	ip_set_id_t index;
 	int ret = 0;
 
 	if (unlikely(protocol_failed(attr) ||
 		     attr[IPSET_ATTR_SETNAME] == NULL))
 		return -IPSET_ERR_PROTOCOL;
 
-	index = find_set_id(nla_data(attr[IPSET_ATTR_SETNAME]));
-	if (index == IPSET_INVALID_ID)
+	set = find_set(nla_data(attr[IPSET_ATTR_SETNAME]));
+	if (set == NULL)
 		return -ENOENT;
-	set = ip_set_list[index];
 
 	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (skb2 == NULL)
@@ -1684,6 +1756,7 @@  ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 	}
 	case IP_SET_OP_GET_BYNAME: {
 		struct ip_set_req_get_set *req_get = data;
+		ip_set_id_t id;
 
 		if (*len != sizeof(struct ip_set_req_get_set)) {
 			ret = -EINVAL;
@@ -1691,12 +1764,14 @@  ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 		}
 		req_get->set.name[IPSET_MAXNAMELEN - 1] = '\0';
 		nfnl_lock();
-		req_get->set.index = find_set_id(req_get->set.name);
+		find_set_and_id(req_get->set.name, &id);
+		req_get->set.index = id;
 		nfnl_unlock();
 		goto copy;
 	}
 	case IP_SET_OP_GET_BYINDEX: {
 		struct ip_set_req_get_set *req_get = data;
+		struct ip_set *set;
 
 		if (*len != sizeof(struct ip_set_req_get_set) ||
 		    req_get->set.index >= ip_set_max) {
@@ -1704,9 +1779,8 @@  ip_set_sockfn_get(struct sock *sk, int optval, void __user *user, int *len)
 			goto done;
 		}
 		nfnl_lock();
-		strncpy(req_get->set.name,
-			ip_set_list[req_get->set.index]
-				? ip_set_list[req_get->set.index]->name : "",
+		set = nfnl_set(req_get->set.index);
+		strncpy(req_get->set.name, set ? set->name : "",
 			IPSET_MAXNAMELEN);
 		nfnl_unlock();
 		goto copy;
@@ -1737,6 +1811,7 @@  static struct nf_sockopt_ops so_set __read_mostly = {
 static int __init
 ip_set_init(void)
 {
+	struct ip_set **list;
 	int ret;
 
 	if (max_sets)
@@ -1744,22 +1819,22 @@  ip_set_init(void)
 	if (ip_set_max >= IPSET_INVALID_ID)
 		ip_set_max = IPSET_INVALID_ID - 1;
 
-	ip_set_list = kzalloc(sizeof(struct ip_set *) * ip_set_max,
-			      GFP_KERNEL);
-	if (!ip_set_list)
+	list = kzalloc(sizeof(struct ip_set *) * ip_set_max, GFP_KERNEL);
+	if (!list)
 		return -ENOMEM;
 
+	rcu_assign_pointer(ip_set_list, list);
 	ret = nfnetlink_subsys_register(&ip_set_netlink_subsys);
 	if (ret != 0) {
 		pr_err("ip_set: cannot register with nfnetlink.\n");
-		kfree(ip_set_list);
+		kfree(list);
 		return ret;
 	}
 	ret = nf_register_sockopt(&so_set);
 	if (ret != 0) {
 		pr_err("SO_SET registry failed: %d\n", ret);
 		nfnetlink_subsys_unregister(&ip_set_netlink_subsys);
-		kfree(ip_set_list);
+		kfree(list);
 		return ret;
 	}
 
@@ -1770,10 +1845,12 @@  ip_set_init(void)
 static void __exit
 ip_set_fini(void)
 {
+	struct ip_set **list = rcu_dereference_protected(ip_set_list, 1);
+
 	/* There can't be any existing set */
 	nf_unregister_sockopt(&so_set);
 	nfnetlink_subsys_unregister(&ip_set_netlink_subsys);
-	kfree(ip_set_list);
+	kfree(list);
 	pr_debug("these are the famous last words\n");
 }