From patchwork Mon Sep 19 10:54:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deepak Kumar Singh X-Patchwork-Id: 12980251 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 9BFE5ECAAD3 for ; Mon, 19 Sep 2022 10:57:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229800AbiISK5Y (ORCPT ); Mon, 19 Sep 2022 06:57:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbiISK5C (ORCPT ); Mon, 19 Sep 2022 06:57:02 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEBFFE71; Mon, 19 Sep 2022 03:54:29 -0700 (PDT) Received: from pps.filterd (m0279862.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28J6Asgl024618; Mon, 19 Sep 2022 10:54:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=qcppdkim1; bh=szSyf/2tC+auA/OTvQr3j+RCEdfxlkRfmtAhj0CEsms=; b=Zv3qhF5urViDyt+eWZaZrtW/7qwvxfEAZ6bVTXDdhVcih0z+XQ45NX5l8V6R5LMlCzvu JguUOrE7pOpIA8ZcjJg+gzkz02ZV/mpojM0VhJW44IGUfiZU39FdxzWP0fv8EpB3Az1X pGtdtj8OVC0nzlai8/ARTW9s/PZd6zPkycynr9V1+79gDlBwxct4XIotANpX3gLYBPXt nNNdOdxqU3WQohWTRq9ZVy4mM02HpeCpLpIMwzcnK1XK/Mv95IuIuhU4nYUUkK/WMshk JfGar4OS38ZKW/3hODghHXEvOhMMl3p8R0DfhA4iklyuz1ndwrqUZMMyGJGI7QGmqQa/ Jw== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3jn70nm964-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 19 Sep 2022 10:54:24 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 28JAsNGO000703 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 19 Sep 2022 10:54:23 GMT Received: from deesin-linux.qualcomm.com (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.29; Mon, 19 Sep 2022 03:54:20 -0700 From: Deepak Kumar Singh To: , , , , CC: , , , Deepak Kumar Singh Subject: [PATCH V5 2/2] rpmsg: ctrl: Add lock to rpmsg_ctrldev_remove Date: Mon, 19 Sep 2022 16:24:00 +0530 Message-ID: <1663584840-15762-3-git-send-email-quic_deesin@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1663584840-15762-1-git-send-email-quic_deesin@quicinc.com> References: <1663584840-15762-1-git-send-email-quic_deesin@quicinc.com> MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: FZeMHd9suSf0SfHsBg3moRupKMeFnGYN X-Proofpoint-ORIG-GUID: FZeMHd9suSf0SfHsBg3moRupKMeFnGYN X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-19_05,2022-09-16_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 adultscore=0 phishscore=0 mlxscore=0 mlxlogscore=917 impostorscore=0 priorityscore=1501 spamscore=0 suspectscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2209190073 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Call to rpmsg_ctrldev_ioctl() and rpmsg_ctrldev_remove() must be synchronized. In present code rpmsg_ctrldev_remove() is not protected with lock, therefore new char device creation can succeed through rpmsg_ctrldev_ioctl() call. At the same time call to rpmsg_ctrldev_remove() function for ctrl device removal will free associated rpdev device. As char device creation already succeeded, user space is free to issue open() call which maps to rpmsg_create_ept() in kernel. rpmsg_create_ept() function tries to reference rpdev which has already been freed through rpmsg_ctrldev_remove(). Issue is predominantly seen in aggressive reboot tests where rpmsg_ctrldev_ioctl() and rpmsg_ctrldev_remove() can race with each other. Adding lock in rpmsg_ctrldev_remove() avoids any new char device creation through rpmsg_ctrldev_ioctl() while remove call is already in progress. Signed-off-by: Deepak Kumar Singh --- drivers/rpmsg/rpmsg_ctrl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c index 107da70..4332538 100644 --- a/drivers/rpmsg/rpmsg_ctrl.c +++ b/drivers/rpmsg/rpmsg_ctrl.c @@ -194,10 +194,12 @@ static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev) struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev); int ret; + mutex_lock(&ctrldev->ctrl_lock); /* Destroy all endpoints */ ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy); if (ret) dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); + mutex_unlock(&ctrldev->ctrl_lock); cdev_device_del(&ctrldev->cdev, &ctrldev->dev); put_device(&ctrldev->dev);