Merge tag 'cgroup-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/…

…linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:

 - Add Waiman Long as a cpuset maintainer

 - cgroup_get_from_id() could be fed a kernfs ID which doesn't point to
   a cgroup directory but a knob file and then crash. Error out if the
   lookup kernfs_node isn't a directory.

* tag 'cgroup-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: cgroup_get_from_id() must check the looked-up kn is a directory
  cpuset: Add Waiman Long as a cpuset maintainer

MAINTAINERS

@@ -5246,6 +5246,7 @@ F:	block/blk-throttle.c
 F:	include/linux/blk-cgroup.h
 
 CONTROL GROUP - CPUSET
+M:	Waiman Long <longman@redhat.com>
 M:	Zefan Li <lizefan.x@bytedance.com>
 L:	cgroups@vger.kernel.org
 S:	Maintained

kernel/cgroup/cgroup.c

@@ -6049,14 +6049,17 @@ struct cgroup *cgroup_get_from_id(u64 id)
 	if (!kn)
 		goto out;
 
+	if (kernfs_type(kn) != KERNFS_DIR)
+		goto put;
+
 	rcu_read_lock();
 
 	cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
 	if (cgrp && !cgroup_tryget(cgrp))
 		cgrp = NULL;
 
 	rcu_read_unlock();
-
+put:
 	kernfs_put(kn);
 out:
 	return cgrp;