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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54CF3C433B4 for ; Mon, 5 Apr 2021 10:19:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 284DC6139C for ; Mon, 5 Apr 2021 10:19:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241162AbhDEKTU (ORCPT ); Mon, 5 Apr 2021 06:19:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:52282 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241151AbhDEKTS (ORCPT ); Mon, 5 Apr 2021 06:19:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E83E361399; Mon, 5 Apr 2021 10:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617617952; bh=rd8LEjO/uhcqPSOwrQIOXBSJlpMdwgd0/QOwQoJAV/o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0AjI0xm1lli8E5jQojcxugwJgxGnNekw7zKxW/Kep1yJ4NBQ7HFjcIZgpEWUzS8Ej QaZgyMxrLor6zLv0bqCrW0FJVFNfmNZsCzLNmX6ub3yEFRM1pc6E1NVlTFPXGit/It PzO/EVUMyk8HFrcHzw0bE/ac7SEWmSNRJwzCeTXI= Date: Mon, 5 Apr 2021 12:19:10 +0200 From: Greg KH To: Hillf Danton Cc: Hao Sun , Jiri Slaby , linux-kernel@vger.kernel.org Subject: Re: KASAN: use-after-free Read in cdev_del Message-ID: References: <20210404123934.2620-1-hdanton@sina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210404123934.2620-1-hdanton@sina.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 04, 2021 at 08:39:34PM +0800, Hillf Danton wrote: > On Sun, 4 Apr 2021 17:05:17 Hao Sun wrote: > > Besides, the 'refcount bug in cdev_del' bug still exists too. > > Thanks for your report, Hao. > > > > Here is the detailed information: > > commit: 5e46d1b78a03d52306f21f77a4e4a144b6d31486 > > version: Linux 5.12-rc5 > > git tree: upstream > > kernel config (KASAN not enabled) and reproducing program can be found > > in the attachment. > > Report: > > ------------[ cut here ]------------ > > refcount_t: underflow; use-after-free. > > WARNING: CPU: 1 PID: 8923 at lib/refcount.c:28 > > refcount_warn_saturate+0x1cf/0x210 -origin/lib/refcount.c:28 > > Modules linked in: > > CPU: 1 PID: 8923 Comm: executor Not tainted 5.12.0-rc5+ #8 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > 1.13.0-1ubuntu1.1 04/01/2014 > > RIP: 0010:refcount_warn_saturate+0x1cf/0x210 -origin/lib/refcount.c:28 > > Code: 4f ff ff ff e8 32 fa b5 fe 48 c7 c7 3d f8 f6 86 e8 d6 ab c6 fe > > c6 05 7c 34 67 04 01 48 c7 c7 68 f8 6d 86 31 c0 e8 81 2e 9d fe <0f> 0b > > e9 22 ff ff ff e8 05 fa b5 fe 48 c7 c7 3e f8 f6 86 e8 a9 ab > > RSP: 0018:ffffc90001633c60 EFLAGS: 00010246 > > RAX: 15d08b2e34b77800 RBX: 0000000000000003 RCX: ffff88804c056c80 > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > > RBP: 0000000000000003 R08: ffffffff813767aa R09: 0001ffffffffffff > > R10: 0001ffffffffffff R11: ffff88804c056c80 R12: ffff888040b7d000 > > R13: ffff88804c206938 R14: ffff88804c206900 R15: ffff888041b18488 > > FS: 00000000022c9940(0000) GS:ffff88807ec00000(0000) knlGS:000000000000000= > > 0 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f9f9b122008 CR3: 0000000044b4b000 CR4: 0000000000750ee0 > > PKRU: 55555554 > > Call Trace: > > __refcount_sub_and_test -origin/./include/linux/refcount.h:283 [inline] > > __refcount_dec_and_test -origin/./include/linux/refcount.h:315 [inline] > > refcount_dec_and_test -origin/./include/linux/refcount.h:333 [inline] > > kref_put -origin/./include/linux/kref.h:64 [inline] > > kobject_put+0x17b/0x180 -origin/lib/kobject.c:753 > > cdev_del+0x4b/0x50 -origin/fs/char_dev.c:597 > > tty_unregister_device+0x99/0xd0 -origin/drivers/tty/tty_io.c:3343 > > gsmld_detach_gsm -origin/drivers/tty/n_gsm.c:2409 [inline] > > gsmld_close+0x6c/0x140 -origin/drivers/tty/n_gsm.c:2478 > > tty_ldisc_close -origin/drivers/tty/tty_ldisc.c:488 [inline] > > tty_ldisc_kill -origin/drivers/tty/tty_ldisc.c:636 [inline] > > tty_ldisc_release+0x1b6/0x400 -origin/drivers/tty/tty_ldisc.c:809 > > tty_release_struct+0x19/0xb0 -origin/drivers/tty/tty_io.c:1714 > > tty_release+0x9ad/0xa00 -origin/drivers/tty/tty_io.c:1885 > > __fput+0x260/0x4e0 -origin/fs/file_table.c:280 > > ____fput+0x11/0x20 -origin/fs/file_table.c:313 > > task_work_run+0x8e/0x110 -origin/kernel/task_work.c:140 > > tracehook_notify_resume -origin/./include/linux/tracehook.h:189 [inline] > > exit_to_user_mode_loop -origin/kernel/entry/common.c:174 [inline] > > exit_to_user_mode_prepare+0x16b/0x1a0 -origin/kernel/entry/common.c:208 > > __syscall_exit_to_user_mode_work -origin/kernel/entry/common.c:290 [inline] > > syscall_exit_to_user_mode+0x20/0x40 -origin/kernel/entry/common.c:301 > > do_syscall_64+0x45/0x80 -origin/arch/x86/entry/common.c:56 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > No error check on registering tty device - add it. > And roll back in case of error. > > --- x/drivers/tty/n_gsm.c > +++ y/drivers/tty/n_gsm.c > @@ -2384,8 +2384,19 @@ static int gsmld_attach_gsm(struct tty_s > /* Don't register device 0 - this is the control channel and not > a usable tty interface */ > base = mux_num_to_base(gsm); /* Base for this MUX */ > - for (i = 1; i < NUM_DLCI; i++) > - tty_register_device(gsm_tty_driver, base + i, NULL); > + for (i = 1; i < NUM_DLCI; i++) { > + struct device *dev; > + > + dev = tty_register_device(gsm_tty_driver, > + base + i, NULL); > + if (IS_ERR(dev)) { > + for (i--; i >= 1; i--) > + tty_unregister_device(gsm_tty_driver, > + base + i); > + ret = PTR_ERR(dev); > + return ret; > + } > + } > } > return ret; > } Are you testing these patches somehow? Can you do that and then submit them correctly? thanks, greg k-h