[PATCH 5/5] netfilter: ipset: Fix calling ip_set() macro at dumping

[Jozsef Kadlecsik]

The ip_set() macro is called when either ip_set_ref_lock held only
or no lock/nfnl mutex is held at dumping. Take this into account
properly.

Signed-off-by: Jozsef Kadlecsik <kad...@blackhole.kfki.hu>
---
 net/netfilter/ipset/ip_set_core.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_core.c 
b/net/netfilter/ipset/ip_set_core.c
index 68db946..292f7c7 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -55,12 +55,27 @@ MODULE_AUTHOR("Jozsef Kadlecsik 
<kad...@blackhole.kfki.hu>");
 MODULE_DESCRIPTION("core IP set support");
 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_IPSET);
 
-/* When the nfnl mutex is held: */
+/* When the nfnl mutex or ip_set_ref_lock is held: */
 #define ip_set_dereference(p)          \
-       rcu_dereference_protected(p, lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET))
+       rcu_dereference_protected(p,    \
+               lockdep_nfnl_is_held(NFNL_SUBSYS_IPSET) || \
+               lockdep_is_held(&ip_set_ref_lock))
 #define ip_set(inst, id)               \
        ip_set_dereference((inst)->ip_set_list)[id]
 
+/* When the nfnl mutex is not held (dumping): */
+static inline
+struct ip_set * ip_set_no_mutex(struct ip_set_net *inst, ip_set_id_t id)
+{
+       struct ip_set *set;
+
+       rcu_read_lock();
+       set = rcu_dereference((inst)->ip_set_list)[id];
+       rcu_read_unlock();
+
+       return set;
+}
+
 /* The set types are implemented in modules and registered set types
  * can be found in ip_set_type_list. Adding/deleting types is
  * serialized by ip_set_type_mutex.
@@ -1251,7 +1266,7 @@ ip_set_dump_done(struct netlink_callback *cb)
                struct ip_set_net *inst =
                        (struct ip_set_net *)cb->args[IPSET_CB_NET];
                ip_set_id_t index = (ip_set_id_t)cb->args[IPSET_CB_INDEX];
-               struct ip_set *set = ip_set(inst, index);
+               struct ip_set *set = ip_set_no_mutex(inst, index);
 
                if (set->variant->uref)
                        set->variant->uref(set, cb, false);
@@ -1440,7 +1455,7 @@ ip_set_dump_start(struct sk_buff *skb, struct 
netlink_callback *cb)
 release_refcount:
        /* If there was an error or set is done, release set */
        if (ret || !cb->args[IPSET_CB_ARG0]) {
-               set = ip_set(inst, index);
+               set = ip_set_no_mutex(inst, index);
                if (set->variant->uref)
                        set->variant->uref(set, cb, false);
                pr_debug("release set %s\n", set->name);
-- 
2.1.4