1 files changed, 32 insertions, 1 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9837bebf93ce..2d8d8fcfa060 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -353,15 +353,46 @@ void __rtnl_link_unregister(struct rtnl_link_ops *ops)
 }
 EXPORT_SYMBOL_GPL(__rtnl_link_unregister);
 
+/* Return with the rtnl_lock held when there are no network
+ * devices unregistering in any network namespace.
+ */
+static void rtnl_lock_unregistering_all(void)
+{
+        struct net *net;
+        bool unregistering;
+        DEFINE_WAIT(wait);
+
+        for (;;) {
+                prepare_to_wait(&netdev_unregistering_wq, &wait,
+                                TASK_UNINTERRUPTIBLE);
+                unregistering = false;
+                rtnl_lock();
+                for_each_net(net) {
+                        if (net->dev_unreg_count > 0) {
+                                unregistering = true;
+                                break;
+                        }
+                }
+                if (!unregistering)
+                        break;
+                __rtnl_unlock();
+                schedule();
+        }
+        finish_wait(&netdev_unregistering_wq, &wait);
+}
+
 /**
  * rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
  * @ops: struct rtnl_link_ops * to unregister
  */
 void rtnl_link_unregister(struct rtnl_link_ops *ops)
 {
-        rtnl_lock();
+        /* Close the race with cleanup_net() */
+        mutex_lock(&net_mutex);
+        rtnl_lock_unregistering_all();
         __rtnl_link_unregister(ops);
         rtnl_unlock();
+        mutex_unlock(&net_mutex);
 }
 EXPORT_SYMBOL_GPL(rtnl_link_unregister);