genetlink: synchronize socket closing and family removal

[pandora-kernel.git] / net / netlink / af_netlink.c

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 84ea76c..02fdde2 100644 (file)
--- 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;