From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5E4CC54EBE for ; Mon, 16 Jan 2023 16:28:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233055AbjAPQ21 (ORCPT ); Mon, 16 Jan 2023 11:28:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233120AbjAPQ2E (ORCPT ); Mon, 16 Jan 2023 11:28:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C74236B1E for ; Mon, 16 Jan 2023 08:16:20 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0B6F560FDF for ; Mon, 16 Jan 2023 16:16:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 234F7C433D2; Mon, 16 Jan 2023 16:16:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885779; bh=7fDL6ifeWM7ucuXChkgoQZqGTDnl1pjDLbz2deqESaE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gAQptAFrjK6aR4hTpx7yXG3jVeOUdq+f4H7ipxG9Hs+IgqVMiQqzPaXt0xjZYhHav Mq0gpxVgNmh1bdg82S55OloOXOhXclJGHWa5/lw3Rbqv+Qb7LRUvOFzoOOxySA9O9u DgdqVt0JssAuGM4HMfE7s48LgP0jEtbcPqoKvEys= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chen Zhongjin , Christoph Hellwig , Sasha Levin Subject: [PATCH 5.4 180/658] configfs: fix possible memory leak in configfs_create_dir() Date: Mon, 16 Jan 2023 16:44:28 +0100 Message-Id: <20230116154917.688062360@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chen Zhongjin [ Upstream commit c65234b283a65cfbfc94619655e820a5e55199eb ] kmemleak reported memory leaks in configfs_create_dir(): unreferenced object 0xffff888009f6af00 (size 192): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) new_fragment (./include/linux/slab.h:600 fs/configfs/dir.c:163) configfs_register_subsystem (fs/configfs/dir.c:1857) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... unreferenced object 0xffff888003ba7180 (size 96): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) configfs_new_dirent (./include/linux/slab.h:723 fs/configfs/dir.c:194) configfs_make_dirent (fs/configfs/dir.c:248) configfs_create_dir (fs/configfs/dir.c:296) configfs_attach_group.isra.28 (fs/configfs/dir.c:816 fs/configfs/dir.c:852) configfs_register_subsystem (fs/configfs/dir.c:1881) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... This is because the refcount is not correct in configfs_make_dirent(). For normal stage, the refcount is changing as: configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() configfs_new_dirent() # set s_count = 1 dentry->d_fsdata = configfs_get(sd); # s_count = 2 ... configfs_unregister_subsystem() configfs_remove_dir() remove_dir() configfs_remove_dirent() # s_count = 1 dput() ... *dentry_unlink_inode()* configfs_d_iput() # s_count = 0, release However, if we failed in configfs_create(): configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() # s_count = 2 ... configfs_create() # fail ->out_remove: configfs_remove_dirent(dentry) configfs_put(sd) # s_count = 1 return PTR_ERR(inode); There is no inode in the error path, so the configfs_d_iput() is lost and makes sd and fragment memory leaked. To fix this, when we failed in configfs_create(), manually call configfs_put(sd) to keep the refcount correct. Fixes: 7063fbf22611 ("[PATCH] configfs: User-driven configuration filesystem") Signed-off-by: Chen Zhongjin Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin --- fs/configfs/dir.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index d73d88d9c259..bc27e3ad97ff 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -317,6 +317,7 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry, return 0; out_remove: + configfs_put(dentry->d_fsdata); configfs_remove_dirent(dentry); return PTR_ERR(inode); } @@ -383,6 +384,7 @@ int configfs_create_link(struct configfs_dirent *target, struct dentry *parent, return 0; out_remove: + configfs_put(dentry->d_fsdata); configfs_remove_dirent(dentry); return PTR_ERR(inode); } -- 2.35.1