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Commit f31e5f1a authored by Xin Long's avatar Xin Long Committed by Pablo Neira Ayuso
Browse files

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: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 2db3fec5

net/ipv4/netfilter/arp_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -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:

net/ipv4/netfilter/ip_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -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:

net/ipv6/netfilter/ip6_tables.c

+2 −1
Original line number Diff line number Diff line
@@ -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: