On Thu, 2017-03-09 at 14:42 +1100, Jonathan Maxwell wrote: > Sorry let me resend in plain text mode. > > On Thu, Mar 9, 2017 at 1:10 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > On Thu, 2017-03-09 at 12:15 +1100, Jon Maxwell wrote: > >> We have seen a few incidents lately where a dst_enty has been freed > >> with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that > >> dst_entry. If the conditions/timings are right a crash then ensues when the > >> freed dst_entry is referenced later on. A Common crashing back trace is: > > > > Very nice catch ! > > > > Thanks Eric. > > > Don't we have a similar issue for IPv6 ? > > > > > > Good point. > > We checked and as far as we can tell IPv6 does not invalidate the route. > So it should be safer. Simply doing : __sk_dst_check(sk, np->dst_cookie); is racy, even before calling dst->ops->redirect(dst, sk, skb); (if socket is owned by user) -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
