Containers: css_put() dilemma

[Paul (宝瑠) Menage]

On 7/17/07, Balbir Singh <balbir at linux.vnet.ibm.com> wrote:
> >
> > >                mutex_lock(&container_mutex);
> > >                set_bit(CONT_RELEASABLE, &cont->flags);
> > >-               if (atomic_dec_and_test(&css->refcnt)) {
> > >-                       check_for_release(cont);
> > >-               }
> > >+               check_for_release(cont);
> > >                mutex_unlock(&container_mutex);
> > >

I think that this isn't safe as it stands, without a synchronize_rcu()
in container_diput() prior to the kfree(). Also, it will break if
anyone tries to use a release agent on a hierarchy that has your
memory controller bound to it.

Paul