cgroups: fix lock inconsistency in cgroup_clone() (1404f065) · Commits · 戴 / test

kernel/cgroup.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -2993,20 +2993,21 @@ int cgroup_clone(struct task_struct tsk, struct cgroup_subsys subsys,
		mutex_unlock(&cgroup_mutex);
		return 0;
		}
		task_lock(tsk);
		cg = tsk->cgroups;
		parent = task_cgroup(tsk, subsys->subsys_id);

		/* Pin the hierarchy */
		if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
		if (!atomic_inc_not_zero(&root->sb->s_active)) {
		/* We race with the final deactivate_super() */
		mutex_unlock(&cgroup_mutex);
		return 0;
		}

		/* Keep the cgroup alive */
		task_lock(tsk);
		parent = task_cgroup(tsk, subsys->subsys_id);
		cg = tsk->cgroups;
		get_css_set(cg);
		task_unlock(tsk);

		mutex_unlock(&cgroup_mutex);

		/* Now do the VFS work to create a cgroup */
		@@ -3045,7 +3046,7 @@ int cgroup_clone(struct task_struct tsk, struct cgroup_subsys subsys,
		mutex_unlock(&inode->i_mutex);
		put_css_set(cg);

		deactivate_super(parent->root->sb);
		deactivate_super(root->sb);
		/* The cgroup is still accessible in the VFS, but
		* we're not going to try to rmdir() it at this
		* point. */
		@@ -3071,7 +3072,7 @@ int cgroup_clone(struct task_struct tsk, struct cgroup_subsys subsys,
		mutex_lock(&cgroup_mutex);
		put_css_set(cg);
		mutex_unlock(&cgroup_mutex);
		deactivate_super(parent->root->sb);
		deactivate_super(root->sb);
		return ret;
		}