Merge tag 'configfs-for-5.2' of git://git.infradead.org/users/hch/con…

…figfs

Pull configfs update from Christoph Hellwig:

 - a fix for an error path use after free (YueHaibing)

* tag 'configfs-for-5.2' of git://git.infradead.org/users/hch/configfs:
  configfs: fix possible use-after-free in configfs_register_group

fs/configfs/dir.c

@@ -1757,12 +1757,19 @@ int configfs_register_group(struct config_group *parent_group,
 
 	inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
 	ret = create_default_group(parent_group, group);
-	if (!ret) {
-		spin_lock(&configfs_dirent_lock);
-		configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
-		spin_unlock(&configfs_dirent_lock);
-	}
+	if (ret)
+		goto err_out;
+
+	spin_lock(&configfs_dirent_lock);
+	configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
+	spin_unlock(&configfs_dirent_lock);
+	inode_unlock(d_inode(parent));
+	return 0;
+err_out:
 	inode_unlock(d_inode(parent));
+	mutex_lock(&subsys->su_mutex);
+	unlink_group(group);
+	mutex_unlock(&subsys->su_mutex);
 	return ret;
 }
 EXPORT_SYMBOL(configfs_register_group);