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 1690CCCA47B for ; Mon, 13 Jun 2022 13:21:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376268AbiFMNVG (ORCPT ); Mon, 13 Jun 2022 09:21:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377080AbiFMNUA (ORCPT ); Mon, 13 Jun 2022 09:20:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7630969CD2; Mon, 13 Jun 2022 04:23:13 -0700 (PDT) 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 C61F961036; Mon, 13 Jun 2022 11:22:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0909C34114; Mon, 13 Jun 2022 11:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655119355; bh=9yTrZd1tTo7lkmuhZLIBbWQ8EWpTWQx/plwALCaKlq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xc7AIo7n+YssxHG/xrzxXYbXRuxS2CR4bOT4eeDPgQEr4m0h64ohQTd9NRfW+WvUa /vxNY8Z2kkPvIB2Nou/kRzJ0Ua8cocI/Zc21NTAvy/3MwzKXZkPWQDiZVTyUzOZKt4 MUod5jAnlzis53K1IRKV9jZ/mzqt7LfRolKlG5j4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Xie Yongji , "Michael S. Tsirkin" Subject: [PATCH 5.15 233/247] vduse: Fix NULL pointer dereference on sysfs access Date: Mon, 13 Jun 2022 12:12:15 +0200 Message-Id: <20220613094930.011057293@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094922.843438024@linuxfoundation.org> References: <20220613094922.843438024@linuxfoundation.org> User-Agent: quilt/0.66 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: Xie Yongji commit b27ee76c74dc831d6e092eaebc2dfc9c0beed1c9 upstream. The control device has no drvdata. So we will get a NULL pointer dereference when accessing control device's msg_timeout attribute via sysfs: [ 132.841881][ T3644] BUG: kernel NULL pointer dereference, address: 00000000000000f8 [ 132.850619][ T3644] RIP: 0010:msg_timeout_show (drivers/vdpa/vdpa_user/vduse_dev.c:1271) [ 132.869447][ T3644] dev_attr_show (drivers/base/core.c:2094) [ 132.870215][ T3644] sysfs_kf_seq_show (fs/sysfs/file.c:59) [ 132.871164][ T3644] ? device_remove_bin_file (drivers/base/core.c:2088) [ 132.872082][ T3644] kernfs_seq_show (fs/kernfs/file.c:164) [ 132.872838][ T3644] seq_read_iter (fs/seq_file.c:230) [ 132.873578][ T3644] ? __vmalloc_area_node (mm/vmalloc.c:3041) [ 132.874532][ T3644] kernfs_fop_read_iter (fs/kernfs/file.c:238) [ 132.875513][ T3644] __kernel_read (fs/read_write.c:440 (discriminator 1)) [ 132.876319][ T3644] kernel_read (fs/read_write.c:459) [ 132.877129][ T3644] kernel_read_file (fs/kernel_read_file.c:94) [ 132.877978][ T3644] kernel_read_file_from_fd (include/linux/file.h:45 fs/kernel_read_file.c:186) [ 132.879019][ T3644] __do_sys_finit_module (kernel/module.c:4207) [ 132.879930][ T3644] __ia32_sys_finit_module (kernel/module.c:4189) [ 132.880930][ T3644] do_int80_syscall_32 (arch/x86/entry/common.c:112 arch/x86/entry/common.c:132) [ 132.881847][ T3644] entry_INT80_compat (arch/x86/entry/entry_64_compat.S:419) To fix it, don't create the unneeded attribute for control device anymore. Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") Reported-by: kernel test robot Cc: stable@vger.kernel.org Signed-off-by: Xie Yongji Message-Id: <20220426073656.229-1-xieyongji@bytedance.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/vdpa/vdpa_user/vduse_dev.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -1336,9 +1336,9 @@ static int vduse_create_dev(struct vduse dev->minor = ret; dev->msg_timeout = VDUSE_MSG_DEFAULT_TIMEOUT; - dev->dev = device_create(vduse_class, NULL, - MKDEV(MAJOR(vduse_major), dev->minor), - dev, "%s", config->name); + dev->dev = device_create_with_groups(vduse_class, NULL, + MKDEV(MAJOR(vduse_major), dev->minor), + dev, vduse_dev_groups, "%s", config->name); if (IS_ERR(dev->dev)) { ret = PTR_ERR(dev->dev); goto err_dev; @@ -1585,7 +1585,6 @@ static int vduse_init(void) return PTR_ERR(vduse_class); vduse_class->devnode = vduse_devnode; - vduse_class->dev_groups = vduse_dev_groups; ret = alloc_chrdev_region(&vduse_major, 0, VDUSE_DEV_MAX, "vduse"); if (ret)