diff options
authorEric Dumazet <eric.dumazet@gmail.com>2011-05-25 07:34:04 +0000
committerDavid S. Miller <davem@davemloft.net>2011-05-25 17:55:32 -0400
commit2907c35ff64708065e5a7fd54e8ded8263eb3074 (patch)
parent1dcb14d9e874d12bab9ceeba776b742f1682b0a6 (diff)
net: hold rtnl again in dump callbacks
Commit e67f88dd12f6 (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: Eric Dumazet <eric.dumazet@gmail.com> CC: Patrick McHardy <kaber@trash.net> CC: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2 files changed, 8 insertions, 2 deletions
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 3911586e12e4..008dc70b064b 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -602,6 +602,7 @@ static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
+ rcu_read_unlock();
cb->args[1] = idx;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d1644e317e70..2d56cb9b0b94 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -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;
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)
+ __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;