net: initialize skb->peeked when cloning

BugLink: http://bugs.launchpad.net/bugs/1774173

commit b13dda9f upstream.

syzbot reported __skb_try_recv_from_queue() was using skb->peeked
while it was potentially unitialized.

We need to clear it in __skb_clone()

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

net/core/skbuff.c

@@ -898,6 +898,7 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
 	n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
 	n->cloned = 1;
 	n->nohdr = 0;
+	n->peeked = 0;
 	n->destructor = NULL;
 	C(tail);
 	C(end);