From patchwork Mon Jan 31 10:56:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 538915 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 434D1C433EF for ; Mon, 31 Jan 2022 11:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358611AbiAaLAZ (ORCPT ); Mon, 31 Jan 2022 06:00:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358471AbiAaK7w (ORCPT ); Mon, 31 Jan 2022 05:59:52 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D569FC061401; Mon, 31 Jan 2022 02:59:24 -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 ams.source.kernel.org (Postfix) with ESMTPS id 9A070B82A57; Mon, 31 Jan 2022 10:59:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F67DC340E8; Mon, 31 Jan 2022 10:59:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643626762; bh=Wz/w4hNDWFLR4+ezkUUBoMewqb0kz+Z+JvTo/zU9V9w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z6ajhU7LfXz9zEwZvmQAYdwczLZBgyVJ5l76Omkh4g5ivSi8tD4Z5KuIn3fK3LT5g RwAz2KvgHy3nIPxnkPcB3k7qeJwe90Cz9PcrKGIOdVRklU+Pklw8mFAGfOEOQXCykL OEuaSYlFKaww5AT2F1Sfdsr0RpgTiU4AxM7dnD7s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bjorn Andersson , Matthias Kaehlcke , Mathieu Poirier , Stephen Boyd Subject: [PATCH 5.4 30/64] rpmsg: char: Fix race between the release of rpmsg_eptdev and cdev Date: Mon, 31 Jan 2022 11:56:15 +0100 Message-Id: <20220131105216.690902742@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220131105215.644174521@linuxfoundation.org> References: <20220131105215.644174521@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Matthias Kaehlcke commit 7a534ae89e34e9b51acb5a63dd0f88308178b46a upstream. struct rpmsg_eptdev contains a struct cdev. The current code frees the rpmsg_eptdev struct in rpmsg_eptdev_destroy(), but the cdev is a managed object, therefore its release is not predictable and the rpmsg_eptdev could be freed before the cdev is entirely released. The cdev_device_add/del() API was created to address this issue (see commit '233ed09d7fda ("chardev: add helper function to register char devs with a struct device")'), use it instead of cdev add/del(). Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") Suggested-by: Bjorn Andersson Signed-off-by: Matthias Kaehlcke Reviewed-by: Mathieu Poirier Reviewed-by: Stephen Boyd Reviewed-by: Bjorn Andersson Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220110104706.v6.2.Idde68b05b88d4a2e6e54766c653f3a6d9e419ce6@changeid Signed-off-by: Greg Kroah-Hartman --- drivers/rpmsg/rpmsg_char.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -92,7 +92,7 @@ static int rpmsg_eptdev_destroy(struct d /* wake up any blocked readers */ wake_up_interruptible(&eptdev->readq); - device_del(&eptdev->dev); + cdev_device_del(&eptdev->cdev, &eptdev->dev); put_device(&eptdev->dev); return 0; @@ -336,7 +336,6 @@ static void rpmsg_eptdev_release_device( ida_simple_remove(&rpmsg_ept_ida, dev->id); ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt)); - cdev_del(&eptdev->cdev); kfree(eptdev); } @@ -381,19 +380,13 @@ static int rpmsg_eptdev_create(struct rp dev->id = ret; dev_set_name(dev, "rpmsg%d", ret); - ret = cdev_add(&eptdev->cdev, dev->devt, 1); + ret = cdev_device_add(&eptdev->cdev, &eptdev->dev); if (ret) goto free_ept_ida; /* We can now rely on the release function for cleanup */ dev->release = rpmsg_eptdev_release_device; - ret = device_add(dev); - if (ret) { - dev_err(dev, "device_add failed: %d\n", ret); - put_device(dev); - } - return ret; free_ept_ida: