Re: Possible netfilter-related memory corruption in 2.6.37

Eric Dumazet
2011-02-14T16:29:15Z

Le lundi 14 février 2011 à 17:24 +0100, Patrick McHardy a écrit :
> Am 14.02.2011 16:50, schrieb Eric Dumazet:
> > Le lundi 14 février 2011 à 16:18 +0100, Jan Engelhardt a écrit :
> >> On Monday 2011-02-14 16:11, Eric Dumazet wrote:
> >>
> >>> Le lundi 14 février 2011 à 16:58 +0200, Avi Kivity a écrit :
> >>>> We see severe memory corruption in kvm while used in conjunction with
> >>>> bridge/netfilter. Enabling slab debugging points the finger at a
> >>>> netfilter chain invoked from the bridge code.
> >>>>
> >>>> Can someone take a look?
> >>>>
> >>>> https://bugzilla.kernel.org/show_bug.cgi?id=27052
> >>
> >> Maybe looks familiar to https://lkml.org/lkml/2011/2/3/147
> >
> > Are you sure Jan ?
> >
> > IMHO it looks like in your case, a NULL ->hook() is called, from
> > nf_iterate()
> >
> > BTW, list_for_each_continue_rcu() really should be converted to
> > list_for_each_entry_continue_rcu()
> >
> > This is a bit ugly :
> >
> > list_for_each_continue_rcu(*i, head) {
> > struct nf_hook_ops *elem = (struct nf_hook_ops *)*i;
> >
> > Also, I wonder if RCU rules are respected in nf_iterate().
> > For example this line is really suspicious :
> >
> > *i = (*i)->prev;
>
> Yeah, that definitely looks wrong. How about this instead?
>

This patch seems fine to me, thanks !

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>