From: David Vrabel Date: Tue, 9 Dec 2014 18:43:28 +0000 (+0000) Subject: xen-netfront: use correct linear area after linearizing an skb X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=11d3d2a16cc1f05c6ece69a4392e99efb85666a6;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git xen-netfront: use correct linear area after linearizing an skb Commit 97a6d1bb2b658ac85ed88205ccd1ab809899884d (xen-netfront: Fix handling packets on compound pages with skb_linearize) attempted to fix a problem where an skb that would have required too many slots would be dropped causing TCP connections to stall. However, it filled in the first slot using the original buffer and not the new one and would use the wrong offset and grant access to the wrong page. Netback would notice the malformed request and stop all traffic on the VIF, reporting: vif vif-3-0 vif3.0: txreq.offset: 85e, size: 4002, end: 6144 vif vif-3-0 vif3.0: fatal error; disabling device Reported-by: Anthony Wright Tested-by: Anthony Wright Signed-off-by: David Vrabel Signed-off-by: David S. Miller --- diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index ece8d1804d13..eeed0ce620f3 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -627,6 +627,9 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) slots, skb->len); if (skb_linearize(skb)) goto drop; + data = skb->data; + offset = offset_in_page(data); + len = skb_headlen(skb); } spin_lock_irqsave(&queue->tx_lock, flags);