| Message ID | 1476901218-15635-1-git-send-email-xiyou.wangcong@gmail.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 2016-10-19 at 11:20 -0700, Cong Wang wrote: > 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> > --- > 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(); Certainly not. Some people want IPv6 being reasonably fast. > ipv6_sock_mc_close(sk); > + rtnl_unlock(); >
On Wed, Oct 19, 2016 at 4:38 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> 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(); > > Certainly not. > > Some people want IPv6 being reasonably fast. Oh, good catch, I should move the 'if' check out too...
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,
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> --- net/ipv6/af_inet6.c | 2 ++ net/ipv6/ipv6_sockglue.c | 1 + net/ipv6/mcast.c | 4 ++-- 3 files changed, 5 insertions(+), 2 deletions(-)