Now it's doing cleanup_entry for oldinfo under the xt_table lock,
but it's not really necessary. After the replacement job is done
in xt_replace_table, oldinfo is not used elsewhere any more, and
it can be freed without xt_table lock safely.
The important thing is that rtnl_lock is called in some xt_target
destroy, which means rtnl_lock, a big lock is used in xt_table
lock, a smaller one. It usually could be the reason why a dead
lock may happen.
Besides, all xt_target/match checkentry is called out of xt_table
lock. It's better also to move all cleanup_entry calling out of
xt_table lock, just as do_replace_finish does for ebtables.
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
net/ipv4/netfilter/arp_tables.c | 3 ++-
net/ipv4/netfilter/ip_tables.c | 3 ++-
net/ipv6/netfilter/ip6_tables.c | 3 ++-
3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 4ffe302..f6c7404 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -921,6 +921,8 @@ static int __do_replace(struct net *net, const char *name,
(newinfo->number <= oldinfo->initial_entries))
module_put(t->me);
+ xt_table_unlock(t);
+
get_old_counters(oldinfo, counters);
/* Decrease module usage counts and free resource */
@@ -935,7 +937,6 @@ static int __do_replace(struct net *net, const char *name,
net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
}
vfree(counters);
- xt_table_unlock(t);
return ret;
put_module:
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 9a71f31..a6517c1 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1082,6 +1082,8 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
(newinfo->number <= oldinfo->initial_entries))
module_put(t->me);
+ xt_table_unlock(t);
+
get_old_counters(oldinfo, counters);
/* Decrease module usage counts and free resource */
@@ -1095,7 +1097,6 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n");
}
vfree(counters);
- xt_table_unlock(t);
return ret;
put_module:
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index af4c917..96577c9 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1101,6 +1101,8 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
(newinfo->number <= oldinfo->initial_entries))
module_put(t->me);
+ xt_table_unlock(t);
+
get_old_counters(oldinfo, counters);
/* Decrease module usage counts and free resource */
@@ -1114,7 +1116,6 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
net_warn_ratelimited("ip6tables: counters copy to user failed while replacing table\n");
}
vfree(counters);
- xt_table_unlock(t);
return ret;
put_module:
--
2.1.0
--
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