ClabureDB: Classified Bug-Reports Database

        if (!cgroup_lock_live_group(cgrp))
                return -ENODEV;
        ret = attach_task_by_pid(cgrp, pid);
        cgroup_unlock();
        return ret;
}

/* The various types of files and directories in a cgroup file system */
enum cgroup_filetype {
        FILE_ROOT,
        FILE_DIR,
        FILE_TASKLIST,
        FILE_NOTIFY_ON_RELEASE,
        FILE_RELEASE_AGENT,
};

/**
 * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive.
 * @cgrp: the cgroup to be checked for liveness
 *
 * On success, returns true; the lock should be later released with
 * cgroup_unlock(). On failure returns false with no lock held.
 */
bool cgroup_lock_live_group(struct cgroup *cgrp)
{
        mutex_lock(&cgroup_mutex);
        if (cgroup_is_removed(cgrp)) {
                mutex_unlock(&cgroup_mutex);
                return false;
        }
        return true;
}

static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
                                      const char *buffer)
{
        BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
        if (!cgroup_lock_live_group(cgrp))
                return -ENODEV;
        strcpy(cgrp->root->release_agent_path, buffer);
        cgroup_unlock();