tipc: Fix unsafe device list search when enabling bearer

Ensures that the device list lock is held while trying to locate
the Ethernet device used by a newly enabled bearer, so that the
addition or removal of a device does not cause problems.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/tipc/eth_media.c b/net/tipc/eth_media.c
index b69092eb95d8..69bedd8a297b 100644
--- a/net/tipc/eth_media.c
+++ b/net/tipc/eth_media.c
@@ -2,7 +2,7 @@
  * net/tipc/eth_media.c: Ethernet bearer support for TIPC
  *
  * Copyright (c) 2001-2007, Ericsson AB
- * Copyright (c) 2005-2007, Wind River Systems
+ * Copyright (c) 2005-2008, 2011, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -144,12 +144,15 @@ static int enable_bearer(struct tipc_bearer *tb_ptr)
 
         /* Find device with specified name */
 
+        read_lock(&dev_base_lock);
         for_each_netdev(&init_net, pdev) {
                 if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
                         dev = pdev;
+                        dev_hold(dev);
                         break;
                 }
         }
+        read_unlock(&dev_base_lock);
         if (!dev)
                 return -ENODEV;
 
@@ -166,7 +169,6 @@ static int enable_bearer(struct tipc_bearer *tb_ptr)
                 eb_ptr->tipc_packet_type.func = recv_msg;
                 eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
                 INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
-                dev_hold(dev);
                 dev_add_pack(&eb_ptr->tipc_packet_type);
         }