From patchwork Mon Sep 19 10:53:59 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: 12980250 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 A6AAAC6FA82 for ; Mon, 19 Sep 2022 10:57:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230158AbiISK5V (ORCPT ); Mon, 19 Sep 2022 06:57:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229713AbiISK5B (ORCPT ); Mon, 19 Sep 2022 06:57:01 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B06D112A; Mon, 19 Sep 2022 03:54:26 -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 28J7rSSO019184; Mon, 19 Sep 2022 10:54:21 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=A2j0MRKCtFKOt7VutTqnUdXi2BId9g8TnNi5kcZ+Ync=; b=jC363IHXqBNlpIC9G44S78I6Y3+cAC8SyyH0C3N+JUma3bDmrxwXTP9k+WjRbYWQOsUv eSgWIjJ6Rnw4rWPT6RJCp3z4OV2w0H59iCEWsZ1i19XChwytpC97rsXWbIzpCMWQV20j zCc8tpeiHKDPX9xgHYP32eE9BMafTdfWp9Et6sDCM7V4jU7Xch8mRtv85jARXa8d+qbK Ws091wEciiyncPsdaXEyTTZN5MJG1nt+V9fl0zb6QjNe9ziDH+wnQiexgufbbtMXtx7q hkNdTrwUySmyoXSn+OR8EbkKZ4PJ1MkL3TASLuuolJNN3qAgraEeFSWw4taY4i0HD0rB OQ== Received: from nalasppmta04.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3jn70nm95v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 19 Sep 2022 10:54:20 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 28JAsKon015953 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 19 Sep 2022 10:54:20 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 03:54:16 -0700 From: Deepak Kumar Singh To: , , , , CC: , , , Deepak Kumar Singh Subject: [PATCH V5 1/2] rpmsg: char: Add lock to avoid race when rpmsg device is released Date: Mon, 19 Sep 2022 16:23:59 +0530 Message-ID: <1663584840-15762-2-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: b_pGjVhjBzDL88dZOgg62tr6d4OL8lVu X-Proofpoint-ORIG-GUID: b_pGjVhjBzDL88dZOgg62tr6d4OL8lVu 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=999 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 When remote host goes down glink char device channel is freed and associated rpdev is destroyed through rpmsg_chrdev_eptdev_destroy(), At the same time user space apps can still try to open/poll rpmsg char device which will result in calling rpmsg_create_ept()/rpmsg_poll(). These functions will try to reference rpdev which has already been freed through rpmsg_chrdev_eptdev_destroy(). File operation functions and device removal function must be protected with lock. This patch adds existing ept lock in remove function as well. Signed-off-by: Deepak Kumar Singh --- drivers/rpmsg/rpmsg_char.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index 4f21891..5500dc0 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -75,6 +75,7 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); mutex_lock(&eptdev->ept_lock); + eptdev->rpdev = NULL; if (eptdev->ept) { rpmsg_destroy_ept(eptdev->ept); eptdev->ept = NULL; @@ -126,6 +127,11 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) return -EBUSY; } + if (!eptdev->rpdev) { + mutex_unlock(&eptdev->ept_lock); + return -ENETRESET; + } + get_device(dev); /* @@ -277,7 +283,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait) if (!skb_queue_empty(&eptdev->queue)) mask |= EPOLLIN | EPOLLRDNORM; + mutex_lock(&eptdev->ept_lock); mask |= rpmsg_poll(eptdev->ept, filp, wait); + mutex_unlock(&eptdev->ept_lock); return mask; }