Commit 2907c35f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: hold rtnl again in dump callbacks 



Commit e67f88dd (dont hold rtnl mutex during netlink dump callbacks)
missed fact that rtnl_fill_ifinfo() must be called with rtnl held.

Because of possible deadlocks between two mutexes (cb_mutex and rtnl),
its not easy to solve this problem, so revert this part of the patch.

It also forgot one rcu_read_unlock() in FIB dump_rules()

Add one ASSERT_RTNL() in rtnl_fill_ifinfo() to remind us the rule.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1dcb14d9

net/core/fib_rules.c

+1 −0
Original line number Diff line number Diff line
@@ -602,6 +602,7 @@ static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb, 
skip:

		idx++;

	}

	rcu_read_unlock();

	cb->args[1] = idx;

	rules_ops_put(ops);

net/core/rtnetlink.c

+7 −2
Original line number Diff line number Diff line
@@ -850,6 +850,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, 
	struct nlattr *attr, *af_spec;

	struct rtnl_af_ops *af_ops;



	ASSERT_RTNL();

	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);

	if (nlh == NULL)

		return -EMSGSIZE;
@@ -1876,6 +1877,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
	int min_len;

	int family;

	int type;

	int err;



	type = nlh->nlmsg_type;

	if (type > RTM_MAX)
@@ -1902,8 +1904,11 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
		if (dumpit == NULL)

			return -EOPNOTSUPP;



		__rtnl_unlock();

		rtnl = net->rtnl;

		return netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);

		err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);

		rtnl_lock();

		return err;

	}



	memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));
@@ -1975,7 +1980,7 @@ static int __net_init rtnetlink_net_init(struct net *net) 
{

	struct sock *sk;

	sk = netlink_kernel_create(net, NETLINK_ROUTE, RTNLGRP_MAX,

				   rtnetlink_rcv, NULL, THIS_MODULE);

				   rtnetlink_rcv, &rtnl_mutex, THIS_MODULE);

	if (!sk)

		return -ENOMEM;

	net->rtnl = sk;

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