gro: Fix page ref count for skbs freed normally
authorHerbert Xu <herbert@gondor.apana.org.au>
Thu, 15 Jan 2009 04:40:03 +0000 (20:40 -0800)
committerDavid S. Miller <davem@davemloft.net>
Thu, 15 Jan 2009 04:40:03 +0000 (20:40 -0800)
When an skb with page frags is merged into an existing one, we
cannibalise its reference count.  This is OK when the skb is
reused because we set nr_frags to zero in that case.  However,
for the case where the skb is freed through kfree_skb, we didn't
clear nr_frags which causes the page to be freed prematurely.

This is fixed by moving the skb resetting into skb_gro_receive.

Reported-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/core/dev.c
net/core/skbuff.c

index 7dec715293b1d40b1fb770354b552ed88e429c9c..60377b6c0a804798a41ce8d128421a41226c25f1 100644 (file)
@@ -2491,12 +2491,6 @@ EXPORT_SYMBOL(napi_gro_receive);
 
 void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 {
-       skb_shinfo(skb)->nr_frags = 0;
-
-       skb->len -= skb->data_len;
-       skb->truesize -= skb->data_len;
-       skb->data_len = 0;
-
        __skb_pull(skb, skb_headlen(skb));
        skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
 
index 5110b359c758c2e8abe7d13e5f63f90269fbbd5e..65eac77390337e9857c73736618a60ff09737d84 100644 (file)
@@ -2602,6 +2602,12 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
                       skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
 
                skb_shinfo(p)->nr_frags += skb_shinfo(skb)->nr_frags;
+               skb_shinfo(skb)->nr_frags = 0;
+
+               skb->truesize -= skb->data_len;
+               skb->len -= skb->data_len;
+               skb->data_len = 0;
+
                NAPI_GRO_CB(skb)->free = 1;
                goto done;
        }