diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index f9628fc20fec..796a6cd5f302 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -50,6 +50,14 @@ DECLARE_RWSEM(configfs_rename_sem);
  */
 DEFINE_SPINLOCK(configfs_dirent_lock);
 
+/*
+ * All of link_obj/unlink_obj/link_group/unlink_group require that
+ * subsys->su_mutex is held.
+ * But parent configfs_subsystem is NULL when config_item is root.
+ * Use this mutex when config_item is root.
+ */
+static DEFINE_MUTEX(configfs_subsystem_mutex);
+
 static void configfs_d_iput(struct dentry * dentry,
 			    struct inode * inode)
 {
@@ -1937,7 +1945,9 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 		group->cg_item.ci_name = group->cg_item.ci_namebuf;
 
 	sd = root->d_fsdata;
+	mutex_lock(&configfs_subsystem_mutex);
 	link_group(to_config_group(sd->s_element), group);
+	mutex_unlock(&configfs_subsystem_mutex);
 
 	inode_lock_nested(d_inode(root), I_MUTEX_PARENT);
 
@@ -1962,7 +1972,9 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 	inode_unlock(d_inode(root));
 
 	if (err) {
+		mutex_lock(&configfs_subsystem_mutex);
 		unlink_group(group);
+		mutex_unlock(&configfs_subsystem_mutex);
 		configfs_release_fs();
 	}
 	put_fragment(frag);
@@ -2008,7 +2020,9 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
 
 	dput(dentry);
 
+	mutex_lock(&configfs_subsystem_mutex);
 	unlink_group(group);
+	mutex_unlock(&configfs_subsystem_mutex);
 	configfs_release_fs();
 }