From: Xin Xiaohui <xiaohui....@intel.com>

>2) The idea to key off of skb->dev in skb_release_data() is
>   fundamentally flawed since many actions can change skb->dev on you,
>   which will end up causing a leak of your external data areas.

How about this one? If the destructor_arg is not a good candidate,
then I have to add an apparent field in shinfo.

Thanks
Xiaohui

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 10ba67d..ad4636e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -199,14 +199,15 @@ struct skb_shared_info {
        struct sk_buff  *frag_list;
        struct skb_shared_hwtstamps hwtstamps;
 
+       /* Intermediate layers must ensure that destructor_arg
+        * remains valid until skb destructor */
+       void *          destructor_arg;
+
        /*
         * Warning : all fields before dataref are cleared in __alloc_skb()
         */
        atomic_t        dataref;
 
-       /* Intermediate layers must ensure that destructor_arg
-        * remains valid until skb destructor */
-       void *          destructor_arg;
        /* must be last field, see pskb_expand_head() */
        skb_frag_t      frags[MAX_SKB_FRAGS];
 };
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index c83b421..eb040f4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -343,6 +343,13 @@ static void skb_release_data(struct sk_buff *skb)
                if (skb_has_frags(skb))
                        skb_drop_fraglist(skb);
 
+               if (skb_shinfo(skb)->destructor_arg) {
+                       struct skb_ext_page *ext_page =
+                               skb_shinfo(skb)->destructor_arg;
+                       if (ext_page->dtor)
+                               ext_page->dtor(ext_page);
+               }
+
                kfree(skb->head);
        }
 }
-- 
1.7.3

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