Re: PATCH? net/bridge/br_if.c: fix use after free in port_carrier_check()

Oleg Nesterov
2007-02-20T14:34:16Z

On 02/20, David Howells wrote:
>
> Oleg Nesterov <oleg@tv-sign.ru> wrote:
>
> > static void release_nbp(struct kobject *kobj)
> > {
> > struct net_bridge_port *p
> > = container_of(kobj, struct net_bridge_port, kobj);
> > +
> > + dev_put(p->dev);
>
> Does this need to be done with the mutex held?

I think no. At least the current code does dev_put() without mutex held.

> And does anything actually pay
> attention to the refcount on dev? I assume not...

I guess net/core/dev.c:netdev_wait_allrefs(), but not sure.

> Should you clear p->dev->br_port before calling dev_put()?

Looks like it is protected by RCU... Anyway the current code does the same.

> Looks reasonable. I like it.
>
> Acked-By: David Howells <dhowells@redhat.com>

Thanks! I'll re-send with a proper changelog later today.

Oleg.