1 files changed, 19 insertions, 9 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 84ea76ca3f1f..75532efa51cd 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>
@@ -1095,6 +1096,8 @@ static void netlink_remove(struct sock *sk)
                 __sk_del_bind_node(sk);
                 netlink_update_listeners(sk);
         }
+        if (sk->sk_protocol == NETLINK_GENERIC)
+                atomic_inc(&genl_sk_destructing_cnt);
         netlink_table_ungrab();
 }
 
@@ -1211,6 +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);
 
@@ -1246,13 +1263,6 @@ static int netlink_release(struct socket *sock)
                 netlink_table_ungrab();
         }
 
-        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);
-        }
         kfree(nlk->groups);
         nlk->groups = NULL;
 
@@ -1428,7 +1438,7 @@ static void netlink_undo_bind(int group, long unsigned int groups,
 
         for (undo = 0; undo < group; undo++)
                 if (test_bit(undo, &groups))
-                        nlk->netlink_unbind(sock_net(sk), undo);
+                        nlk->netlink_unbind(sock_net(sk), undo + 1);
 }
 
 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
@@ -1466,7 +1476,7 @@ 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(net, group);
+                        err = nlk->netlink_bind(net, group + 1);
                         if (!err)
                                 continue;
                         netlink_undo_bind(group, groups, sk);