On Wed, 2017-03-15 at 15:08 -0700, David Miller wrote:
> From: Eric Dumazet <eric.duma...@gmail.com>
> Date: Wed, 15 Mar 2017 09:10:33 -0700
>
> > @@ -692,12 +692,17 @@ void __sock_recv_timestamp(struct msghdr *msg, struct
> > sock *sk,
> > ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2))
> > empty = 0;
> > if (!empty) {
> > + unsigned int hlen = skb_headlen(skb);
> > +
> > put_cmsg(msg, SOL_SOCKET,
> > SCM_TIMESTAMPING, sizeof(tss), &tss);
> >
> > - if (skb->len && (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS))
> > + if (hlen &&
> > + (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
> > + sk->sk_protocol == IPPROTO_TCP &&
> > + sk->sk_type == SOCK_STREAM)
> > put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS,
> > - skb->len, skb->data);
> > + hlen, skb->data);
>
> Hmmm, what is the true intention of SOF_TIMESTAMPING_OPT_STATS then? The
> existing code seems to want to dump the entire SKB into the cmsg, and if
> that's the case then the fix is to linearlize the skb before the put_cmsg()
> or have a way to put a non-linear SKB into a cmsg.
I simply matched the conditions in __skb_tstamp_tx() which builds the
skb :
+ if (tsonly) {
+#ifdef CONFIG_INET
+ if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
+ sk->sk_protocol == IPPROTO_TCP &&
+ sk->sk_type == SOCK_STREAM)
+ skb = tcp_get_timestamping_opt_stats(sk);
+ else
+#endif
+ skb = alloc_skb(0, GFP_ATOMIC);
+ } else {
And note that I should have also used the #ifdef
A proper fix would be to find a bit in skb->cb[] to avoid duplicating
the test...
