1 files changed, 33 insertions, 15 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 074cf3e91c6f..02fdde28dada 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -61,6 +61,7 @@
 #include <linux/rhashtable.h>
 #include <asm/cacheflush.h>
 #include <linux/hash.h>
+#include <linux/genetlink.h>
 
 #include <net/net_namespace.h>
 #include <net/sock.h>
@@ -1091,8 +1092,12 @@ static void netlink_remove(struct sock *sk)
         mutex_unlock(&nl_sk_hash_lock);
 
         netlink_table_grab();
-        if (nlk_sk(sk)->subscriptions)
+        if (nlk_sk(sk)->subscriptions) {
                 __sk_del_bind_node(sk);
+                netlink_update_listeners(sk);
+        }
+        if (sk->sk_protocol == NETLINK_GENERIC)
+                atomic_inc(&genl_sk_destructing_cnt);
         netlink_table_ungrab();
 }
 
@@ -1139,8 +1144,8 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
         struct module *module = NULL;
         struct mutex *cb_mutex;
         struct netlink_sock *nlk;
-        int (*bind)(int group);
-        void (*unbind)(int group);
+        int (*bind)(struct net *net, int group);
+        void (*unbind)(struct net *net, int group);
         int err = 0;
 
         sock->state = SS_UNCONNECTED;
@@ -1209,6 +1214,20 @@ static int netlink_release(struct socket *sock)
          * will be purged.
          */
 
+        /* must not acquire netlink_table_lock in any way again before unbind
+         * and notifying genetlink is done as otherwise it might deadlock
+         */
+        if (nlk->netlink_unbind) {
+                int i;
+
+                for (i = 0; i < nlk->ngroups; i++)
+                        if (test_bit(i, nlk->groups))
+                                nlk->netlink_unbind(sock_net(sk), i + 1);
+        }
+        if (sk->sk_protocol == NETLINK_GENERIC &&
+            atomic_dec_return(&genl_sk_destructing_cnt) == 0)
+                wake_up(&genl_sk_destructing_waitq);
+
         sock->sk = NULL;
         wake_up_interruptible_all(&nlk->wait);
 
@@ -1226,8 +1245,8 @@ static int netlink_release(struct socket *sock)
 
         module_put(nlk->module);
 
-        netlink_table_grab();
         if (netlink_is_kernel(sk)) {
+                netlink_table_grab();
                 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
                 if (--nl_table[sk->sk_protocol].registered == 0) {
                         struct listeners *old;
@@ -1241,10 +1260,8 @@ static int netlink_release(struct socket *sock)
                         nl_table[sk->sk_protocol].flags = 0;
                         nl_table[sk->sk_protocol].registered = 0;
                 }
-        } else if (nlk->subscriptions) {
-                netlink_update_listeners(sk);
+                netlink_table_ungrab();
         }
-        netlink_table_ungrab();
 
         kfree(nlk->groups);
         nlk->groups = NULL;
@@ -1410,9 +1427,10 @@ static int netlink_realloc_groups(struct sock *sk)
         return err;
 }
 
-static void netlink_unbind(int group, long unsigned int groups,
-                           struct netlink_sock *nlk)
+static void netlink_undo_bind(int group, long unsigned int groups,
+                              struct sock *sk)
 {
+        struct netlink_sock *nlk = nlk_sk(sk);
         int undo;
 
         if (!nlk->netlink_unbind)
@@ -1420,7 +1438,7 @@ static void netlink_unbind(int group, long unsigned int groups,
 
         for (undo = 0; undo < group; undo++)
                 if (test_bit(undo, &groups))
-                        nlk->netlink_unbind(undo);
+                        nlk->netlink_unbind(sock_net(sk), undo);
 }
 
 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
@@ -1458,10 +1476,10 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
                 for (group = 0; group < nlk->ngroups; group++) {
                         if (!test_bit(group, &groups))
                                 continue;
-                        err = nlk->netlink_bind(group);
+                        err = nlk->netlink_bind(net, group);
                         if (!err)
                                 continue;
-                        netlink_unbind(group, groups, nlk);
+                        netlink_undo_bind(group, groups, sk);
                         return err;
                 }
         }
@@ -1471,7 +1489,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
                         netlink_insert(sk, net, nladdr->nl_pid) :
                         netlink_autobind(sock);
                 if (err) {
-                        netlink_unbind(nlk->ngroups, groups, nlk);
+                        netlink_undo_bind(nlk->ngroups, groups, sk);
                         return err;
                 }
         }
@@ -2122,7 +2140,7 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
                 if (!val || val - 1 >= nlk->ngroups)
                         return -EINVAL;
                 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
-                        err = nlk->netlink_bind(val);
+                        err = nlk->netlink_bind(sock_net(sk), val);
                         if (err)
                                 return err;
                 }
@@ -2131,7 +2149,7 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
                                          optname == NETLINK_ADD_MEMBERSHIP);
                 netlink_table_ungrab();
                 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
-                        nlk->netlink_unbind(val);
+                        nlk->netlink_unbind(sock_net(sk), val);
 
                 err = 0;
                 break;