4.9-stable review patch. If anyone has any objections, please let me know.
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From: Juergen Gross jgross@suse.com
[ Upstream commit d81c5054a5d1d4999c7cdead7636b6cd4af83d36 ]
At least old Xen net backends seem to send frags with no real data sometimes. In case such a fragment happens to occur with the frag limit already reached the frontend will BUG currently even if this situation is easily recoverable.
Modify the BUG_ON() condition accordingly.
Tested-by: Dietmar Hahn dietmar.hahn@ts.fujitsu.com Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/xen-netfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -903,7 +903,7 @@ static RING_IDX xennet_fill_frags(struct 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)); + BUG_ON(pull_to < skb_headlen(skb)); __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); } if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {