From patchwork Tue Apr 13 00:10:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tyrel Datwyler X-Patchwork-Id: 419757 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 11E2DC433ED for ; Tue, 13 Apr 2021 00:10:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D851861369 for ; Tue, 13 Apr 2021 00:10:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344277AbhDMAKj (ORCPT ); Mon, 12 Apr 2021 20:10:39 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:24346 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239862AbhDMAKj (ORCPT ); Mon, 12 Apr 2021 20:10:39 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13D033Au074297; Mon, 12 Apr 2021 20:10:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=b5OkmVCIlgrSNkc0HXVFd7Y74lhcvJOs79Gyz/bi1os=; b=BFd4OOshzYxytYPezKs8Lp5ocCWZK8R3xLxMHAsQMUhkLngtJ8TUwg20j4lk90jggkfb MWrhzWNXBMtuxQtT/7Wi5ovFIT99PQfJic85dc2l3BdT7mBCCjn8baz/3yMUKFKtCDXb 1q9Gp0kT58BsmcJwEebudUmEXwWjkoe82ZkSup2Uc85spDUQHR6Nn+DjULELFKNyrpGN Ef+mtj1uP0ZTuj16Z2NRqSQ0GzPDfoGjduJp9sXrEqSlPNQPaORdsUX44zYzjC8mIKmE KIpbtmyWgkNx2TLk97od/VY8IPa8WQKaF2EwwS62azELvSCEWSNeANuC+/vrfweqzizB YQ== Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0a-001b2d01.pphosted.com with ESMTP id 37uskah5xy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 12 Apr 2021 20:10:13 -0400 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.0.43/8.16.0.43) with SMTP id 13D08APE026827; Tue, 13 Apr 2021 00:10:12 GMT Received: from b03cxnp08026.gho.boulder.ibm.com (b03cxnp08026.gho.boulder.ibm.com [9.17.130.18]) by ppma02dal.us.ibm.com with ESMTP id 37u3n9hcuk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 13 Apr 2021 00:10:12 +0000 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08026.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 13D0ABJT20906406 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 13 Apr 2021 00:10:11 GMT Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2B1C5BE053; Tue, 13 Apr 2021 00:10:11 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C135EBE04F; Tue, 13 Apr 2021 00:10:10 +0000 (GMT) Received: from vios4361.aus.stglabs.ibm.com (unknown [9.3.43.61]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 13 Apr 2021 00:10:10 +0000 (GMT) From: Tyrel Datwyler To: james.bottomley@hansenpartnership.com Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, brking@linux.ibm.com, Brian King , Tyrel Datwyler Subject: [PATCH] ibmvfc: Fix invalid state machine BUG_ON Date: Mon, 12 Apr 2021 18:10:09 -0600 Message-Id: <20210413001009.902400-1-tyreld@linux.ibm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 9A9OYfiBUiRlRes3E9Oel-LhcAYgExpD X-Proofpoint-GUID: 9A9OYfiBUiRlRes3E9Oel-LhcAYgExpD X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.761 definitions=2021-04-12_11:2021-04-12,2021-04-12 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 clxscore=1011 mlxscore=0 mlxlogscore=999 phishscore=0 lowpriorityscore=0 spamscore=0 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104120158 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Brian King This fixes an issue hitting the BUG_ON in ibmvfc_do_work. When going through a host action of IBMVFC_HOST_ACTION_RESET, we change the action to IBMVFC_HOST_ACTION_TGT_DEL, then drop the host lock, and reset the CRQ, which changes the host state to IBMVFC_NO_CRQ. If, prior to setting the host state to IBMVFC_NO_CRQ, ibmvfc_init_host is called, it can then end up changing the host action to IBMVFC_HOST_ACTION_INIT. If we then change the host state to IBMVFC_NO_CRQ, we will then hit the BUG_ON. This patch makes a couple of changes to avoid this. It leaves the host action to be IBMVFC_HOST_ACTION_RESET or IBMVFC_HOST_ACTION_REENABLE until after we drop the host lock and reset or reenable the CRQ. It also hardens the host state machine to ensure we cannot leave the reset / reenable state until we've finished processing the reset or reenable. Fixes: 73ee5d867287 ("[SCSI] ibmvfc: Fix soft lockup on resume") Signed-off-by: Brian King [tyreld: added fixes tag] Signed-off-by: Tyrel Datwyler --- drivers/scsi/ibmvscsi/ibmvfc.c | 53 ++++++++++++++++++++++------------ 1 file changed, 34 insertions(+), 19 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index 61831f2fdb30..f813608d74cc 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.c +++ b/drivers/scsi/ibmvscsi/ibmvfc.c @@ -603,8 +603,17 @@ static void ibmvfc_set_host_action(struct ibmvfc_host *vhost, if (vhost->action == IBMVFC_HOST_ACTION_ALLOC_TGTS) vhost->action = action; break; + case IBMVFC_HOST_ACTION_REENABLE: + case IBMVFC_HOST_ACTION_RESET: + vhost->action = action; + break; case IBMVFC_HOST_ACTION_INIT: case IBMVFC_HOST_ACTION_TGT_DEL: + case IBMVFC_HOST_ACTION_LOGO: + case IBMVFC_HOST_ACTION_QUERY_TGTS: + case IBMVFC_HOST_ACTION_TGT_DEL_FAILED: + case IBMVFC_HOST_ACTION_NONE: + default: switch (vhost->action) { case IBMVFC_HOST_ACTION_RESET: case IBMVFC_HOST_ACTION_REENABLE: @@ -614,15 +623,6 @@ static void ibmvfc_set_host_action(struct ibmvfc_host *vhost, break; } break; - case IBMVFC_HOST_ACTION_LOGO: - case IBMVFC_HOST_ACTION_QUERY_TGTS: - case IBMVFC_HOST_ACTION_TGT_DEL_FAILED: - case IBMVFC_HOST_ACTION_NONE: - case IBMVFC_HOST_ACTION_RESET: - case IBMVFC_HOST_ACTION_REENABLE: - default: - vhost->action = action; - break; } } @@ -5373,30 +5373,45 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost) case IBMVFC_HOST_ACTION_INIT_WAIT: break; case IBMVFC_HOST_ACTION_RESET: - vhost->action = IBMVFC_HOST_ACTION_TGT_DEL; list_splice_init(&vhost->purge, &purge); spin_unlock_irqrestore(vhost->host->host_lock, flags); ibmvfc_complete_purge(&purge); rc = ibmvfc_reset_crq(vhost); + spin_lock_irqsave(vhost->host->host_lock, flags); - if (rc == H_CLOSED) + if (!rc || rc == H_CLOSED) vio_enable_interrupts(to_vio_dev(vhost->dev)); - if (rc || (rc = ibmvfc_send_crq_init(vhost)) || - (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) { - ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD); - dev_err(vhost->dev, "Error after reset (rc=%d)\n", rc); + if (vhost->action == IBMVFC_HOST_ACTION_RESET) { + /* The only action we could have changed to would have been reenable, + in which case, we skip the rest of this path and wait until + we've done the re-enable before sending the crq init */ + + vhost->action = IBMVFC_HOST_ACTION_TGT_DEL; + + if (rc || (rc = ibmvfc_send_crq_init(vhost)) || + (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) { + ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD); + dev_err(vhost->dev, "Error after reset (rc=%d)\n", rc); + } } break; case IBMVFC_HOST_ACTION_REENABLE: - vhost->action = IBMVFC_HOST_ACTION_TGT_DEL; list_splice_init(&vhost->purge, &purge); spin_unlock_irqrestore(vhost->host->host_lock, flags); ibmvfc_complete_purge(&purge); rc = ibmvfc_reenable_crq_queue(vhost); + spin_lock_irqsave(vhost->host->host_lock, flags); - if (rc || (rc = ibmvfc_send_crq_init(vhost))) { - ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD); - dev_err(vhost->dev, "Error after enable (rc=%d)\n", rc); + if (vhost->action == IBMVFC_HOST_ACTION_REENABLE) { + /* The only action we could have changed to would have been reset, + in which case, we skip the rest of this path and wait until + we've done the reset before sending the crq init */ + + vhost->action = IBMVFC_HOST_ACTION_TGT_DEL; + if (rc || (rc = ibmvfc_send_crq_init(vhost))) { + ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD); + dev_err(vhost->dev, "Error after enable (rc=%d)\n", rc); + } } break; case IBMVFC_HOST_ACTION_LOGO: