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| author |   David Vrabel <david.vrabel@citrix.com> | 2015-03-04 11:14:47 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2015-03-05 14:58:17 -0500 |
| commit | 49d9991a18f9aae7b14abbd9c1cc87555330a769 (patch) | |
| tree | f642411098ecbf508d8303abdaacaa7e39642482 /drivers | |
| parent | xen-netback: return correct ethtool stats (diff) | |
| download | linux-dev-49d9991a18f9aae7b14abbd9c1cc87555330a769.tar.xz linux-dev-49d9991a18f9aae7b14abbd9c1cc87555330a769.zip | |
xen-netback: unref frags when handling a from-guest skb with a frag list
Every time a VIF is destroyed up to 256 pages may be leaked if packets
with more than MAX_SKB_FRAGS frags were transmitted from the guest.
Even worse, if another user of ballooned pages allocated one of these
ballooned pages it would not handle the unexpectedly >1 page count
(e.g., gntdev would deadlock when unmapping a grant because the page
count would never reach 1).
When handling a from-guest skb with a frag list, unref the frags
before releasing them so they are freed correctly when the VIF is
destroyed.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/xen-netback/netback.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index c4d68d768408..f1d84fb1eba8 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1349,7 +1349,7 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s { unsigned int offset = skb_headlen(skb); skb_frag_t frags[MAX_SKB_FRAGS]; - int i; + int i, f; struct ubuf_info *uarg; struct sk_buff *nskb = skb_shinfo(skb)->frag_list; @@ -1389,6 +1389,11 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s frags[i].page_offset = 0; skb_frag_size_set(&frags[i], len); } + + /* Release all the original (foreign) frags. */ + for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) + skb_frag_unref(skb, f); + /* swap out with old one */ memcpy(skb_shinfo(skb)->frags, frags, |