Peter Zijlstra <pet...@infradead.org> wrote:
> On Tue, Nov 07, 2017 at 10:47:51AM +0100, Florian Westphal wrote:
> > I would expect this to trigger all the time, due to
> >
> > rtnl_register(AF_INET, RTM_GETROUTE, ...
> > rtnl_register(AF_INET, RTM_GETADDR, ...
>
> Ah, sure, then something like so then...
>
> There's bound to be bugs there too, as I pretty much typed this without
> thinking, but it should show the idea.
Just o let you know, I am backlogged at the moment so I Will not have
time to work on this for the time being.
> ---
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 5ace48926b19..de1336775602 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -63,6 +63,7 @@ struct rtnl_link {
> rtnl_doit_func doit;
> rtnl_dumpit_func dumpit;
> unsigned int flags;
> + struct rcu_head rcu;
> };
This will need to be split:
struct rtnl_link {
rtnl_doit_func doit;
unsigned int flags;
struct rcu_head rcu;
};
struct rtnl_link_dump {
rtnl_dumpit_func dumpit;
struct rcu_head rcu;
};
> -static struct rtnl_link __rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1];
> +static struct rtnl_link __rcu **rtnl_msg_handlers[RTNL_FAMILY_MAX + 1];
So this will need to be two arrays.
Reason is that some places do this:
rtnl_register(pf, RTM_FOO, doit, NULL, 0);
rtnl_register(pf, RTM_FOO, NULL, dumpit, 0);
(from different call sites in the stack).
> - if (doit)
> - tab[msgindex].doit = doit;
> - if (dumpit)
> - tab[msgindex].dumpit = dumpit;
Which is the reason for these if () tests.
