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authorWANG Cong <xiyou.wangcong@gmail.com>2016-10-19 23:35:12 -0700
committerDavid S. Miller <davem@davemloft.net>2016-10-21 11:29:02 -0400
commit8651be8f14a12d24f203f283601d9b0418c389ff (patch)
tree15f086903cd41889f29e23ac2f80d8bb77f7ead4 /net
parent8dbad1a81128f7e224fce3cce28a1d545d9c0b88 (diff)
ipv6: fix a potential deadlock in do_ipv6_setsockopt()
Baozeng reported this deadlock case: CPU0 CPU1 ---- ---- lock([ 165.136033] sk_lock-AF_INET6); lock([ 165.136033] rtnl_mutex); lock([ 165.136033] sk_lock-AF_INET6); lock([ 165.136033] rtnl_mutex); Similar to commit 87e9f0315952 ("ipv4: fix a potential deadlock in mcast getsockopt() path") this is due to we still have a case, ipv6_sock_mc_close(), where we acquire sk_lock before rtnl_lock. Close this deadlock with the similar solution, that is always acquire rtnl lock first. Fixes: baf606d9c9b1 ("ipv4,ipv6: grab rtnl before locking the socket") Reported-by: Baozeng Ding <sploving1@gmail.com> Tested-by: Baozeng Ding <sploving1@gmail.com> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/ipv6_sockglue.c3
-rw-r--r--net/ipv6/mcast.c17
2 files changed, 14 insertions, 6 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 5330262ab673..636ec56f5f50 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -120,6 +120,7 @@ struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
static bool setsockopt_needs_rtnl(int optname)
{
switch (optname) {
+ case IPV6_ADDRFORM:
case IPV6_ADD_MEMBERSHIP:
case IPV6_DROP_MEMBERSHIP:
case IPV6_JOIN_ANYCAST:
@@ -198,7 +199,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
}
fl6_free_socklist(sk);
- ipv6_sock_mc_close(sk);
+ __ipv6_sock_mc_close(sk);
/*
* Sock is moving from IPv6 to IPv4 (sk_prot), so
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 75c1fc54f188..14a3903f1c82 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -276,16 +276,14 @@ static struct inet6_dev *ip6_mc_find_dev_rcu(struct net *net,
return idev;
}
-void ipv6_sock_mc_close(struct sock *sk)
+void __ipv6_sock_mc_close(struct sock *sk)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct ipv6_mc_socklist *mc_lst;
struct net *net = sock_net(sk);
- if (!rcu_access_pointer(np->ipv6_mc_list))
- return;
+ ASSERT_RTNL();
- rtnl_lock();
while ((mc_lst = rtnl_dereference(np->ipv6_mc_list)) != NULL) {
struct net_device *dev;
@@ -303,8 +301,17 @@ void ipv6_sock_mc_close(struct sock *sk)
atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
kfree_rcu(mc_lst, rcu);
-
}
+}
+
+void ipv6_sock_mc_close(struct sock *sk)
+{
+ struct ipv6_pinfo *np = inet6_sk(sk);
+
+ if (!rcu_access_pointer(np->ipv6_mc_list))
+ return;
+ rtnl_lock();
+ __ipv6_sock_mc_close(sk);
rtnl_unlock();
}