FAILED: patch "[PATCH] cgroup: cgroup_get_from_id() must check the looked-up kn is a" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

df02452f3df0 ("cgroup: cgroup_get_from_id() must check the looked-up kn is a directory") be288169712f ("cgroup: reduce dependency on cgroup_mutex")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From df02452f3df069a59bc9e69c84435bf115cb6e37 Mon Sep 17 00:00:00 2001
From: Ming Lei <[email protected]>
Date: Fri, 23 Sep 2022 19:51:19 +0800
Subject: [PATCH] cgroup: cgroup_get_from_id() must check the looked-up kn is a
directory

cgroup has to be one kernfs dir, otherwise kernel panic is caused, especially cgroup id is provide from userspace.

index e4bb5d57f4d1..5f2090d051ac 100644
@@ -6049,6 +6049,9 @@ 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);

@@ -6056,7 +6059,7 @@ struct cgroup *cgroup_get_from_id(u64 id)
 		cgrp = NULL;
 
 	rcu_read_unlock();
-
+put:
 	kernfs_put(kn);
 out:
 	return cgrp;