From: Willem de Bruijn <willemdebruijn.ker...@gmail.com>
Date: Wed, 15 May 2019 13:29:16 -0400
> From: Willem de Bruijn <will...@google.com>
>
> Zerocopy skbs without completion notification were added for packet
> sockets with PACKET_TX_RING user buffers. Those signal completion
> through the TP_STATUS_USER bit in the ring. Zerocopy annotation was
> added only to avoid premature notification after clone or orphan, by
> triggering a copy on these paths for these packets.
>
> The mechanism had to define a special "no-uarg" mode because packet
> sockets already use skb_uarg(skb) == skb_shinfo(skb)->destructor_arg
> for a different pointer.
>
> Before deferencing skb_uarg(skb), verify that it is a real pointer.
>
> Fixes: 5cd8d46ea1562 ("packet: copy user buffers before orphan or clone")
> Signed-off-by: Willem de Bruijn <will...@google.com>
Applied and queued up for -stable, thanks.
