Messages in this thread | | | Date | Wed, 14 May 2014 14:52:54 +0200 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 04/14] device_cgroup: remove direct access to cgroup->children |
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Quoting Tejun Heo (tj@kernel.org): > Currently, devcg::has_children() directly tests cgroup->children for > list emptiness. The field is not a published field and scheduled to > go away. In addition, the test isn't strictly correct as devcg should > only care about children which are visible to userland. > > This patch converts has_children() to use css_next_child() instead. > The subtle incorrectness is noted and will be dealt with later. > > Signed-off-by: Tejun Heo <tj@kernel.org> > Cc: Aristeu Rozanski <aris@redhat.com> > Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
> --- > security/device_cgroup.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/security/device_cgroup.c b/security/device_cgroup.c > index 3116015..75b4b18 100644 > --- a/security/device_cgroup.c > +++ b/security/device_cgroup.c > @@ -477,9 +477,17 @@ static int propagate_exception(struct dev_cgroup *devcg_root, > > static inline bool has_children(struct dev_cgroup *devcgroup) > { > - struct cgroup *cgrp = devcgroup->css.cgroup; > + bool ret; > > - return !list_empty(&cgrp->children); > + /* > + * FIXME: There may be lingering offline csses and this function > + * may return %true when there isn't any userland-visible child > + * which is incorrect for our purposes. > + */ > + rcu_read_lock(); > + ret = css_next_child(NULL, &devcgroup->css); > + rcu_read_unlock(); > + return ret; > } > > /* > -- > 1.9.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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