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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 30 Jan 2019 12:26:58 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0UCQu2U7733672 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 30 Jan 2019 12:26:56 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9DDEDAE055; Wed, 30 Jan 2019 12:26:56 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A0935AE04D; Wed, 30 Jan 2019 12:26:54 +0000 (GMT) Received: from vajain21.in.ibm.com (unknown [9.109.223.93]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 30 Jan 2019 12:26:54 +0000 (GMT) From: Vaibhav Jain To: "Manoj N . Kumar" , "Matthew R . Ochs" , Uma Krishnan Cc: Vaibhav Jain , Frederic Barrat , linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org Subject: [PATCH] scsi: cxlflash: Prevent deadlock when adapter probe fails Date: Wed, 30 Jan 2019 17:56:51 +0530 X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19013012-0012-0000-0000-000002EEE97D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19013012-0013-0000-0000-00002126304F Message-Id: <20190130122651.19255-1-vaibhav@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-30_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901300099 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Presently when an error is encountered during probe of the cxlflash adapter, a deadlock is seen with cpu thread stuck inside cxlflash_remove(). Below is the trace of the deadlock as logged by khungtaskd: cxlflash 0006:00:00.0: cxlflash_probe: init_afu failed rc=-16 INFO: task kworker/80:1:890 blocked for more than 120 seconds. Not tainted 5.0.0-rc4-capi2-kexec+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/80:1 D 0 890 2 0x00000808 Workqueue: events work_for_cpu_fn Call Trace: 0x4d72136320 (unreliable) __switch_to+0x2cc/0x460 __schedule+0x2bc/0xac0 schedule+0x40/0xb0 cxlflash_remove+0xec/0x640 [cxlflash] cxlflash_probe+0x370/0x8f0 [cxlflash] local_pci_probe+0x6c/0x140 work_for_cpu_fn+0x38/0x60 process_one_work+0x260/0x530 worker_thread+0x280/0x5d0 kthread+0x1a8/0x1b0 ret_from_kernel_thread+0x5c/0x80 INFO: task systemd-udevd:5160 blocked for more than 120 seconds. The deadlock occurs as cxlflash_remove() is called from cxlflash_probe() without setting 'cxlflash_cfg->state' to STATE_PROBED and the probe thread starts to wait on 'cxlflash_cfg->reset_waitq'. Since the device was never successfully probed the 'cxlflash_cfg->state' never changes from STATE_PROBING hence the deadlock occurs. We fix this deadlock by setting the variable 'cxlflash_cfg->state' to STATE_PROBED in case an error occurs during cxlflash_probe() and just before calling cxlflash_remove(). Cc: stable@vger.kernel.org Fixes: c21e0bbfc485("cxlflash: Base support for IBM CXL Flash Adapter") Signed-off-by: Vaibhav Jain --- drivers/scsi/cxlflash/main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index bfa13e3b191c..c8bad2c093b8 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -3687,6 +3687,7 @@ static int cxlflash_probe(struct pci_dev *pdev, host->max_cmd_len = CXLFLASH_MAX_CDB_LEN; cfg = shost_priv(host); + cfg->state = STATE_PROBING; cfg->host = host; rc = alloc_mem(cfg); if (rc) { @@ -3775,6 +3776,7 @@ static int cxlflash_probe(struct pci_dev *pdev, return rc; out_remove: + cfg->state = STATE_PROBED; cxlflash_remove(pdev); goto out; } -- 2.20.1 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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F007C282D7 for ; Wed, 30 Jan 2019 12:32:28 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EE1A920882 for ; Wed, 30 Jan 2019 12:32:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE1A920882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43qN6d6Z01zDqNl for ; Wed, 30 Jan 2019 23:32:25 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=vaibhav@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43qN0T4chfzDqLr for ; Wed, 30 Jan 2019 23:27:05 +1100 (AEDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0UCOR3x073320 for ; Wed, 30 Jan 2019 07:27:03 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qbayku01d-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 30 Jan 2019 07:27:02 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 30 Jan 2019 12:26:58 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0UCQu2U7733672 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 30 Jan 2019 12:26:56 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9DDEDAE055; Wed, 30 Jan 2019 12:26:56 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A0935AE04D; Wed, 30 Jan 2019 12:26:54 +0000 (GMT) Received: from vajain21.in.ibm.com (unknown [9.109.223.93]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 30 Jan 2019 12:26:54 +0000 (GMT) From: Vaibhav Jain To: "Manoj N . Kumar" , "Matthew R . Ochs" , Uma Krishnan Subject: [PATCH] scsi: cxlflash: Prevent deadlock when adapter probe fails Date: Wed, 30 Jan 2019 17:56:51 +0530 X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19013012-0012-0000-0000-000002EEE97D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19013012-0013-0000-0000-00002126304F Message-Id: <20190130122651.19255-1-vaibhav@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-01-30_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901300099 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Frederic Barrat , Vaibhav Jain , linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org, linux-scsi@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Presently when an error is encountered during probe of the cxlflash adapter, a deadlock is seen with cpu thread stuck inside cxlflash_remove(). Below is the trace of the deadlock as logged by khungtaskd: cxlflash 0006:00:00.0: cxlflash_probe: init_afu failed rc=-16 INFO: task kworker/80:1:890 blocked for more than 120 seconds. Not tainted 5.0.0-rc4-capi2-kexec+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/80:1 D 0 890 2 0x00000808 Workqueue: events work_for_cpu_fn Call Trace: 0x4d72136320 (unreliable) __switch_to+0x2cc/0x460 __schedule+0x2bc/0xac0 schedule+0x40/0xb0 cxlflash_remove+0xec/0x640 [cxlflash] cxlflash_probe+0x370/0x8f0 [cxlflash] local_pci_probe+0x6c/0x140 work_for_cpu_fn+0x38/0x60 process_one_work+0x260/0x530 worker_thread+0x280/0x5d0 kthread+0x1a8/0x1b0 ret_from_kernel_thread+0x5c/0x80 INFO: task systemd-udevd:5160 blocked for more than 120 seconds. The deadlock occurs as cxlflash_remove() is called from cxlflash_probe() without setting 'cxlflash_cfg->state' to STATE_PROBED and the probe thread starts to wait on 'cxlflash_cfg->reset_waitq'. Since the device was never successfully probed the 'cxlflash_cfg->state' never changes from STATE_PROBING hence the deadlock occurs. We fix this deadlock by setting the variable 'cxlflash_cfg->state' to STATE_PROBED in case an error occurs during cxlflash_probe() and just before calling cxlflash_remove(). Cc: stable@vger.kernel.org Fixes: c21e0bbfc485("cxlflash: Base support for IBM CXL Flash Adapter") Signed-off-by: Vaibhav Jain --- drivers/scsi/cxlflash/main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index bfa13e3b191c..c8bad2c093b8 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -3687,6 +3687,7 @@ static int cxlflash_probe(struct pci_dev *pdev, host->max_cmd_len = CXLFLASH_MAX_CDB_LEN; cfg = shost_priv(host); + cfg->state = STATE_PROBING; cfg->host = host; rc = alloc_mem(cfg); if (rc) { @@ -3775,6 +3776,7 @@ static int cxlflash_probe(struct pci_dev *pdev, return rc; out_remove: + cfg->state = STATE_PROBED; cxlflash_remove(pdev); goto out; } -- 2.20.1