[TIPC]: Fixed skb_under_panic caused by tipc_link_bundle_buf

Now determines tailroom of bundle buffer by directly inspection of buffer.
Previously, buffer was assumed to have a max capacity equal to the link MTU,
but the addition of link MTU negotiation means that the link MTU can increase
after the bundle buffer is allocated.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Per Liden <per.liden@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index d64658053746..c6831c75cfa4 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -2,7 +2,7 @@
  * net/tipc/link.c: TIPC link code
  * 
  * Copyright (c) 1996-2006, Ericsson AB
- * Copyright (c) 2004-2005, Wind River Systems
+ * Copyright (c) 2004-2006, Wind River Systems
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -988,17 +988,18 @@ static int link_bundle_buf(struct link *l_ptr,
         struct tipc_msg *bundler_msg = buf_msg(bundler);
         struct tipc_msg *msg = buf_msg(buf);
         u32 size = msg_size(msg);
-        u32 to_pos = align(msg_size(bundler_msg));
-        u32 rest = link_max_pkt(l_ptr) - to_pos;
+        u32 bundle_size = msg_size(bundler_msg);
+        u32 to_pos = align(bundle_size);
+        u32 pad = to_pos - bundle_size;
 
         if (msg_user(bundler_msg) != MSG_BUNDLER)
                 return 0;
         if (msg_type(bundler_msg) != OPEN_MSG)
                 return 0;
-        if (rest < align(size))
+        if (skb_tailroom(bundler) < (pad + size))
                 return 0;
 
-        skb_put(bundler, (to_pos - msg_size(bundler_msg)) + size);
+        skb_put(bundler, pad + size);
         memcpy(bundler->data + to_pos, buf->data, size);
         msg_set_size(bundler_msg, to_pos + size);
         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);