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| author | WANG Cong <xiyou.wangcong@gmail.com> | 2016-10-19 23:35:12 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-21 11:29:02 -0400 |
| commit | 8651be8f14a12d24f203f283601d9b0418c389ff (patch) | |
| tree | 15f086903cd41889f29e23ac2f80d8bb77f7ead4 /net/ipv6/mcast.c | |
| parent | 8dbad1a81128f7e224fce3cce28a1d545d9c0b88 (diff) | |
| download | linux-8651be8f14a12d24f203f283601d9b0418c389ff.tar.bz2 | |
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/ipv6/mcast.c')
| -rw-r--r-- | net/ipv6/mcast.c | 17 |
1 files changed, 12 insertions, 5 deletions
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(); } |