[Xen-devel] [PATCH] xen/netfront: don't cache skb_shinfo()

[Juergen Gross <jgross@xxxxxxxx>]

skb_shinfo() can change when calling __pskb_pull_tail(): Don't cache
its return value.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/net/xen-netfront.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 2d8812dd1534..9dd2ca62d84a 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -894,7 +894,6 @@ static RING_IDX xennet_fill_frags(struct netfront_queue 
*queue,
                                  struct sk_buff *skb,
                                  struct sk_buff_head *list)
 {
-       struct skb_shared_info *shinfo = skb_shinfo(skb);
        RING_IDX cons = queue->rx.rsp_cons;
        struct sk_buff *nskb;
 
@@ -903,15 +902,16 @@ static RING_IDX xennet_fill_frags(struct netfront_queue 
*queue,
                        RING_GET_RESPONSE(&queue->rx, ++cons);
                skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 
-               if (shinfo->nr_frags == MAX_SKB_FRAGS) {
+               if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
                        unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 
                        BUG_ON(pull_to <= skb_headlen(skb));
                        __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
                }
-               BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
+               BUG_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS);
 
-               skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
+               skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
+                               skb_frag_page(nfrag),
                                rx->offset, rx->status, PAGE_SIZE);
 
                skb_shinfo(nskb)->nr_frags = 0;
-- 
2.13.7


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