diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 18 |
1 files changed, 5 insertions, 13 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 12237a291d88..e76698dd6c08 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4041,7 +4041,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, { struct cgroup *cgrp = dummy_css->cgroup; struct cgroup_event *event; - struct cgroup *cgrp_cfile; + struct cgroup_subsys_state *cfile_css; unsigned int efd, cfd; struct file *efile; struct file *cfile; @@ -4103,7 +4103,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, } /* - * Determine the css of @cfile and associate @event with it. + * Determine the css of @cfile, verify it belongs to the same + * cgroup as cgroup.event_control, and associate @event with it. * Remaining events are automatically removed on cgroup destruction * but the removal is asynchronous, so take an extra ref. */ @@ -4111,23 +4112,14 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, ret = -EINVAL; event->css = cgroup_css(cgrp, event->cft->ss); - if (event->css && css_tryget(event->css)) + cfile_css = css_from_dir(cfile->f_dentry->d_parent, event->cft->ss); + if (event->css && event->css == cfile_css && css_tryget(event->css)) ret = 0; rcu_read_unlock(); if (ret) goto out_put_cfile; - /* - * The file to be monitored must be in the same cgroup as - * cgroup.event_control is. - */ - cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent); - if (cgrp_cfile != cgrp) { - ret = -EINVAL; - goto out_put_css; - } - if (!event->cft->register_event || !event->cft->unregister_event) { ret = -EINVAL; goto out_put_css; |