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 <[email protected]>
Tested-by: Baozeng Ding <[email protected]>
Cc: Marcelo Ricardo Leitner <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
---
net/ipv6/af_inet6.c | 2 ++
net/ipv6/ipv6_sockglue.c | 1 +
net/ipv6/mcast.c | 4 ++--
3 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 46ad699..b8c8d20 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -414,7 +414,9 @@ int inet6_release(struct socket *sock)
return -EINVAL;
/* Free mc lists */
+ rtnl_lock();
ipv6_sock_mc_close(sk);
+ rtnl_unlock();
/* Free ac lists */
ipv6_sock_ac_close(sk);
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 5330262..1e4bcce 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:
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 75c1fc5..41badfd 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -282,10 +282,11 @@ void ipv6_sock_mc_close(struct sock *sk)
struct ipv6_mc_socklist *mc_lst;
struct net *net = sock_net(sk);
+ ASSERT_RTNL();
+
if (!rcu_access_pointer(np->ipv6_mc_list))
return;
- rtnl_lock();
while ((mc_lst = rtnl_dereference(np->ipv6_mc_list)) != NULL) {
struct net_device *dev;
@@ -305,7 +306,6 @@ void ipv6_sock_mc_close(struct sock *sk)
kfree_rcu(mc_lst, rcu);
}
- rtnl_unlock();
}
int ip6_mc_source(int add, int omode, struct sock *sk,
--
2.1.0
