From patchwork Thu May 20 09:21:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 445528 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 858D8C433B4 for ; Thu, 20 May 2021 10:31:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69694611AD for ; Thu, 20 May 2021 10:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236483AbhETKcd (ORCPT ); Thu, 20 May 2021 06:32:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:33412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237225AbhETKac (ORCPT ); Thu, 20 May 2021 06:30:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A59ED619A7; Thu, 20 May 2021 09:51:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621504310; bh=DlQHfCnXIhrxdegb1dh/H5yqveOeP02fhLYol42uChs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TJCsNr73toFHIfRvu6zGk2ZDqjQIp9eP6QG/BU6ChG6/oxd4rlbwWa5lXOaZKws2V SyiNY5Ngx9tGd55sejFkYr9YA9i/iunbibczEiRr40Ru5+08Xc5zwfAzYhu+fmadcT fHFZiDxJCsmalTrgK/GU/UlH2F5/vtPy+DRs0neM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , Kevin Tian , Max Gurtovoy , Cornelia Huck , Jason Gunthorpe , Alex Williamson , Sasha Levin Subject: [PATCH 4.14 187/323] vfio/mdev: Do not allow a mdev_type to have a NULL parent pointer Date: Thu, 20 May 2021 11:21:19 +0200 Message-Id: <20210520092126.523776885@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092120.115153432@linuxfoundation.org> References: <20210520092120.115153432@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jason Gunthorpe [ Upstream commit b5a1f8921d5040bb788492bf33a66758021e4be5 ] There is a small race where the parent is NULL even though the kobj has already been made visible in sysfs. For instance the attribute_group is made visible in sysfs_create_files() and the mdev_type_attr_show() does: ret = attr->show(kobj, type->parent->dev, buf); Which will crash on NULL parent. Move the parent setup to before the type pointer leaves the stack frame. Fixes: 7b96953bc640 ("vfio: Mediated device Core driver") Reviewed-by: Christoph Hellwig Reviewed-by: Kevin Tian Reviewed-by: Max Gurtovoy Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Message-Id: <2-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson Signed-off-by: Sasha Levin --- drivers/vfio/mdev/mdev_sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c index 7e474e41c85e..2dbdefd7b683 100644 --- a/drivers/vfio/mdev/mdev_sysfs.c +++ b/drivers/vfio/mdev/mdev_sysfs.c @@ -108,6 +108,7 @@ struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent, return ERR_PTR(-ENOMEM); type->kobj.kset = parent->mdev_types_kset; + type->parent = parent; ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL, "%s-%s", dev_driver_string(parent->dev), @@ -135,7 +136,6 @@ struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent, } type->group = group; - type->parent = parent; return type; attrs_failed: