From f31e5f1a891f989f107e8caa6b49dd4df0e12265 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 16 Feb 2018 18:04:56 +0800 Subject: [PATCH] netfilter: unlock xt_table earlier in __do_replace 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 Signed-off-by: Pablo Neira Ayuso --- 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: -- 2.30.2