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>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d1644e3..2d56cb9 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -850,6 +850,7 @@
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 @@
int min_len;
int family;
int type;
+ int err;
type = nlh->nlmsg_type;
if (type > RTM_MAX)
@@ -1902,8 +1904,11 @@
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 @@
{
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;
