From patchwork Thu Sep 15 09:44:13 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: 606270 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 DFF52C6FA86 for ; Thu, 15 Sep 2022 09:44:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229711AbiIOJoy (ORCPT ); Thu, 15 Sep 2022 05:44:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229696AbiIOJow (ORCPT ); Thu, 15 Sep 2022 05:44:52 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46A49CE1B; Thu, 15 Sep 2022 02:44:47 -0700 (PDT) Received: from pps.filterd (m0279863.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28EN0qx1026143; Thu, 15 Sep 2022 09:44:41 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=W3zY9QLNPWEAB8o9Gg6uFxsBfJVYFRPkCf7CJNbWhIg=; b=Ixg/8E/v+b3nQVulmN0UBDIf0v1LvJXqXV0mb5oTs704oyQ4xmdTc1agw1wsxPX6ZOFu EaDzqcNUGGI7Biw0qD+cZhgmwLB8AWJnK6LXS3l1o26fN6nBdYzlgp/SNb6IDwDXPHEs gG9YuaV0wSi0Bi+9eQHmIUJUjeVqjsmzh3DNPW4QgkmdQ6biu925Q76FXpOWmTU4s2Da EF6EhNAl57S4ZRKeK2E+Ou8DNZq2A/A6hzlTKJd4Le/hyMYOhmkHr6i8+GiGtUVag39l 5eXnjDSk/l8Mnm5YOc3yZFZKQL5B2u0BwNGnMHdPMsgxka2tExqaotQ5Q+7GpRHDHAV3 vQ== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3jjxyvnxht-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Sep 2022 09:44:41 +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 28F9ieNj027904 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 15 Sep 2022 09:44:40 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; Thu, 15 Sep 2022 02:44:37 -0700 From: Deepak Kumar Singh To: , , , , CC: , , , Deepak Kumar Singh Subject: [PATCH V4 2/2] rpmsg: ctrl: Add lock to rpmsg_ctrldev_remove Date: Thu, 15 Sep 2022 15:14:13 +0530 Message-ID: <1663235055-3081-3-git-send-email-quic_deesin@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1663235055-3081-1-git-send-email-quic_deesin@quicinc.com> References: <1663235055-3081-1-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: AaacIgswq14N5rlTHFr63vN2WdEYfYOZ X-Proofpoint-ORIG-GUID: AaacIgswq14N5rlTHFr63vN2WdEYfYOZ 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=2022-09-15_06,2022-09-14_04,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 adultscore=0 lowpriorityscore=0 spamscore=0 phishscore=0 priorityscore=1501 suspectscore=0 mlxlogscore=941 clxscore=1015 bulkscore=0 impostorscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2208220000 definitions=main-2209150053 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() funtion 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 throught 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);