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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B648C636CB for ; Mon, 30 Jan 2023 08:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229653AbjA3ID4 (ORCPT ); Mon, 30 Jan 2023 03:03:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230024AbjA3IDz (ORCPT ); Mon, 30 Jan 2023 03:03:55 -0500 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADE2312F3B; Mon, 30 Jan 2023 00:03:54 -0800 (PST) Received: from pps.filterd (m0279862.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 30U7CEnm019701; Mon, 30 Jan 2023 08:03:49 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=wUEmNGtY5YBXH0Iwf0vKCRpxgYtWM4Y6TFuANozd8as=; b=CvG7swZbFO20g1stkWC7haQXLYZKqLNbC+RhEPkm6LaeeB3GCkj7a1YlFM6a+4celj+m FvEvkHHwlSiUMoJ30v5hirICE0I0/h5xVb3WI32rOdYCpxNWC2wauruWzDUqyBYhkpM4 HWT0fg4MtIdM/kP0dTFgZMeg8AiXZIVJMfjOssbkO2sIkd8nEn5TxOW3p+7s0Zf9Lulu kFqyCIjBHu2a0WHR1dggpsDup0Lg2A8nt1+CCAgUHmF+/3nDaKEbuTAoctiiSSH2m1u9 /jdCUikGxlFeK/2X/yJ8s/XUcxTBU4Ivb4HkzF3ZUxMKowXr7SdZklx64mKH0dvxUaLO lA== Received: from nasanppmta02.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3ncvfpax72-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 30 Jan 2023 08:03:49 +0000 Received: from nasanex01c.na.qualcomm.com (nasanex01c.na.qualcomm.com [10.45.79.139]) by NASANPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 30U83mjQ018349 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 30 Jan 2023 08:03:48 GMT Received: from [10.216.24.235] (10.80.80.8) by nasanex01c.na.qualcomm.com (10.45.79.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.36; Mon, 30 Jan 2023 00:03:45 -0800 Message-ID: Date: Mon, 30 Jan 2023 13:33:42 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.13.1 Subject: Re: [PATCH] remoteproc: sysfs: fix race while updating recovery flag Content-Language: en-US To: Satya Durga Srinivasu Prabhala , , CC: , , References: <20230129225106.10606-1-quic_satyap@quicinc.com> From: Mukesh Ojha In-Reply-To: <20230129225106.10606-1-quic_satyap@quicinc.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01c.na.qualcomm.com (10.45.79.139) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: PFfgtZ5PI_aMMULWC5h9AeWpLcjoPgCJ X-Proofpoint-ORIG-GUID: PFfgtZ5PI_aMMULWC5h9AeWpLcjoPgCJ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-30_06,2023-01-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 adultscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 priorityscore=1501 phishscore=0 mlxlogscore=921 bulkscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301300075 Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On 1/30/2023 4:21 AM, Satya Durga Srinivasu Prabhala wrote: > When multiple clients try to update the recovery flag, it is Multiple user-space clients ? > possible that, race condition would lead to undesired results > as updates to recovery flag isn't protected by any mechanism > today. To avoid such issues, take remoteproc mutex lock before > updating recovery flag and release the lock once done. But your patch also adds locks for the case which does not update recovery flag.. > > Signed-off-by: Satya Durga Srinivasu Prabhala > --- > drivers/remoteproc/remoteproc_sysfs.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c > index 8c7ea8922638..ec37176e1589 100644 > --- a/drivers/remoteproc/remoteproc_sysfs.c > +++ b/drivers/remoteproc/remoteproc_sysfs.c > @@ -48,16 +48,21 @@ static ssize_t recovery_store(struct device *dev, > { > struct rproc *rproc = to_rproc(dev); > > + mutex_lock(&rproc->lock); > if (sysfs_streq(buf, "enabled")) { > /* change the flag and begin the recovery process if needed */ > rproc->recovery_disabled = false; > + mutex_unlock(&rproc->lock); > rproc_trigger_recovery(rproc); > } else if (sysfs_streq(buf, "disabled")) { > rproc->recovery_disabled = true; > + mutex_unlock(&rproc->lock); > } else if (sysfs_streq(buf, "recover")) { > /* begin the recovery process without changing the flag */ > + mutex_unlock(&rproc->lock); is it really needed for this case? > rproc_trigger_recovery(rproc); > } else { > + mutex_unlock(&rproc->lock); same here.. > return -EINVAL; > } > Do you also need to add lock for rproc_recovery_write in drivers/remoteproc/remoteproc_debugfs.c ? -Mukesh