The attachment contains an UNTESTED patch (though a similar patch was tested 
with a 
3.10 kernel). 

We've been chasing a bug where packet corruption is seen on a tap device. We 
have a 
PACKET_MMAP socket which is bound to a tap interface. When throughput goes 
above a 
threshold, we begin to see that packets received on the tap device are 
truncated, or 
otherwise corrupted. We found that when packets are enqueued to the tap device, 
they 
are fine, but by the time they are read, they can be corrupted. 

And we found that simply deferring the call to skb_orphan() (where the 
destructor, 
tpacket_destruct_skb() marks the frame as TP_STATUS_AVAILABLE) fixes the 
problem. 

Maybe there's a better fix, but this worked for us. Thoughts? (Please CC me on 
replies - I'm not 
subscribed.) 

-- 
Arthur 

Attachment: tun_defer_skb_orphan.patch
Description: tun_defer_skb_orphan.patch

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