Messages in this thread | | | Date | Sat, 2 Feb 2013 16:20:52 +0000 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH v5 9/9] devcg: propagate local changes down the hierarchy |
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Quoting Aristeu Rozanski (aris@redhat.com): > +/** > + * propagate_exception - propagates a new exception to the children > + * @devcg_root: device cgroup that added a new exception > + * > + * returns: 0 in case of success, != 0 in case of error > + */ > +static int propagate_exception(struct dev_cgroup *devcg_root) > +{ > + struct cgroup *root = devcg_root->css.cgroup; > + struct dev_cgroup *devcg, *parent, *tmp; > + int rc = 0; > + LIST_HEAD(pending); > + > + get_online_devcg(root, &pending); > + > + list_for_each_entry_safe(devcg, tmp, &pending, propagate_pending) { > + parent = cgroup_to_devcgroup(devcg->css.cgroup->parent); > + > + dev_exception_clean(&devcg->exceptions); > + if (devcg->behavior == parent->behavior) { > + rc = dev_exceptions_copy(&devcg->exceptions, &parent->exceptions);
Let's say parent A and child B both have DEFAULT_DENY, with a set of let's say 5 whitelist exceptions. Now the parent adds two more whitelist exceptions. As you say, we don't propagate those.
Now the parent removes one of it's whitelist exceptions. devcgroup_update_access() calls dev_exception_rm() followed by propagate_exception(), which comes here and copies the parent's whitelist - including the two new whitelist rules - to the child.
-serge
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