[PATCH 06/47] netfilter: unlock xt_table earlier in __do_replace
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2018-03-30 11:37:48
Also in:
netfilter-devel
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Xin Long <lucien.xin@gmail.com> 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@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> --- 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 c36ffce3c812..a0c7ce76879c 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c@@ -925,6 +925,8 @@ 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 */
@@ -939,7 +941,6 @@ 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 d4f7584d2dbe..4f7153e25e0b 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c@@ -1087,6 +1087,8 @@ __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 */
@@ -1100,7 +1102,6 @@ __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 4de8ac1e5af4..6c44033decab 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c@@ -1105,6 +1105,8 @@ __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 */
@@ -1118,7 +1120,6 @@ __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:
--
2.11.0