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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 81D06C4741F for ; Tue, 29 Sep 2020 12:36:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 148EB2076A for ; Tue, 29 Sep 2020 12:36:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601382982; bh=Y0Y285XeeAWShdejcScb29RREm2zjDV4lO9on/U7ulg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XUkZN7TW/X9b50lwpjj4FdoWFAu2rItL8ARpAk/hCHUoAmt2FthIroB/O3/9kIr29 61ycwoRuU3UHvLP+POLRvhDSh/l/33vf8xq3CfqVPJMLYK0YX0kifS7zGw5FIOesYv msRP2HKz9o1SpH9pzPSv9zp1cFqxioP/3J3oW7jQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733171AbgI2MgR (ORCPT ); Tue, 29 Sep 2020 08:36:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:37028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729311AbgI2LU6 (ORCPT ); Tue, 29 Sep 2020 07:20:58 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5851F2311C; Tue, 29 Sep 2020 11:18:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378302; bh=Y0Y285XeeAWShdejcScb29RREm2zjDV4lO9on/U7ulg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Pf5DvXJgRMZtdntqxtdaB36QiO8acRcGoodmjJfwth/ak0lwIdxpwXGu3yWkHargf XEaZtf5uFzcErZ1QDARw4GvAfO/5ynuyIQs5F7kklTzpVehxfO/n3o8Gbh+ayv/2WD KF9oEZKESmDATwV3heOWne2tJ8Hv7yiTMV+ZGe8k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhuparna Bhowmik , Andrew Morton , Alexandre Bounine , Matt Porter , Dan Carpenter , Mike Marshall , Thomas Gleixner , Ira Weiny , Allison Randal , Pavel Andrianov , Linus Torvalds , Sasha Levin Subject: [PATCH 4.14 133/166] rapidio: avoid data race between file operation callbacks and mport_cdev_add(). Date: Tue, 29 Sep 2020 13:00:45 +0200 Message-Id: <20200929105941.843994421@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105935.184737111@linuxfoundation.org> References: <20200929105935.184737111@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: linux-kernel@vger.kernel.org From: Madhuparna Bhowmik [ Upstream commit e1c3cdb26ab881b77486dc50370356a349077c74 ] Fields of md(mport_dev) are set after cdev_device_add(). However, the file operation callbacks can be called after cdev_device_add() and therefore accesses to fields of md in the callbacks can race with the rest of the mport_cdev_add() function. One such example is INIT_LIST_HEAD(&md->portwrites) in mport_cdev_add(), the list is initialised after cdev_device_add(). This can race with list_add_tail(&pw_filter->md_node,&md->portwrites) in rio_mport_add_pw_filter() which is called by unlocked_ioctl. To avoid such data races use cdev_device_add() after initializing md. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Madhuparna Bhowmik Signed-off-by: Andrew Morton Acked-by: Alexandre Bounine Cc: Matt Porter Cc: Dan Carpenter Cc: Mike Marshall Cc: Thomas Gleixner Cc: Ira Weiny Cc: Allison Randal Cc: Pavel Andrianov Link: http://lkml.kernel.org/r/20200426112950.1803-1-madhuparnabhowmik10@gmail.com Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- drivers/rapidio/devices/rio_mport_cdev.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index f15f6d1e1070a..f207f8725993c 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -2464,13 +2464,6 @@ static struct mport_dev *mport_cdev_add(struct rio_mport *mport) cdev_init(&md->cdev, &mport_fops); md->cdev.owner = THIS_MODULE; - ret = cdev_device_add(&md->cdev, &md->dev); - if (ret) { - rmcd_error("Failed to register mport %d (err=%d)", - mport->id, ret); - goto err_cdev; - } - INIT_LIST_HEAD(&md->doorbells); spin_lock_init(&md->db_lock); INIT_LIST_HEAD(&md->portwrites); @@ -2490,6 +2483,13 @@ static struct mport_dev *mport_cdev_add(struct rio_mport *mport) #else md->properties.transfer_mode |= RIO_TRANSFER_MODE_TRANSFER; #endif + + ret = cdev_device_add(&md->cdev, &md->dev); + if (ret) { + rmcd_error("Failed to register mport %d (err=%d)", + mport->id, ret); + goto err_cdev; + } ret = rio_query_mport(mport, &attr); if (!ret) { md->properties.flags = attr.flags; -- 2.25.1