Re: Possible netfilter-related memory corruption in 2.6.37

Eric Dumazet
2011-02-14T15:50:41Z

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;