From patchwork Wed Nov 20 13:20:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julian Wiedmann X-Patchwork-Id: 1198144 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47J3L71j6Hz9sSV for ; Thu, 21 Nov 2019 00:23:43 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730541AbfKTNXe (ORCPT ); Wed, 20 Nov 2019 08:23:34 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:18844 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727784AbfKTNVI (ORCPT ); Wed, 20 Nov 2019 08:21:08 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xAKDIPh8133541 for ; Wed, 20 Nov 2019 08:21:07 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2wcf57g440-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 20 Nov 2019 08:21:07 -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, 20 Nov 2019 13:21:02 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xAKDL0Bh46465136 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 13:21:00 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9E69252052; Wed, 20 Nov 2019 13:21:00 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 58CDF5204F; Wed, 20 Nov 2019 13:21:00 +0000 (GMT) From: Julian Wiedmann To: David Miller Cc: , , Heiko Carstens , Stefan Raspl , Ursula Braun , Julian Wiedmann Subject: [PATCH net 1/2] s390/qeth: fix potential deadlock on workqueue flush Date: Wed, 20 Nov 2019 14:20:56 +0100 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191120132057.1788-1-jwi@linux.ibm.com> References: <20191120132057.1788-1-jwi@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19112013-0012-0000-0000-00000369D029 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19112013-0013-0000-0000-000021A55FD1 Message-Id: <20191120132057.1788-2-jwi@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95, 18.0.572 definitions=2019-11-20_03:2019-11-15, 2019-11-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=999 priorityscore=1501 suspectscore=0 spamscore=0 impostorscore=0 clxscore=1015 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911200120 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The L2 bridgeport code uses the coarse 'conf_mutex' for guarding access to its configuration state. This can result in a deadlock when qeth_l2_stop_card() - called under the conf_mutex - blocks on flush_workqueue() to wait for the completion of pending bridgeport workers. Such workers would also need to aquire the conf_mutex, stalling indefinitely. Introduce a lock that specifically guards the bridgeport configuration, so that the workers no longer need the conf_mutex. Wrapping qeth_l2_promisc_to_bridge() in this fine-grained lock then also fixes a theoretical race against a concurrent qeth_bridge_port_role_store() operation. Fixes: c0a2e4d10d93 ("s390/qeth: conclude all event processing before offlining a card") Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter --- drivers/s390/net/qeth_core.h | 1 + drivers/s390/net/qeth_l2_main.c | 21 ++++++++++++++------- drivers/s390/net/qeth_l2_sys.c | 14 +++++++++++++- 3 files changed, 28 insertions(+), 8 deletions(-) diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index e4b55f9aa062..65e31df37b1f 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -839,6 +839,7 @@ struct qeth_card { struct service_level qeth_service_level; struct qdio_ssqd_desc ssqd; debug_info_t *debug; + struct mutex sbp_lock; struct mutex conf_mutex; struct mutex discipline_mutex; struct napi_struct napi; diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index bd8143e51747..4bccdce19b5a 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -467,10 +467,14 @@ static void qeth_l2_set_promisc_mode(struct qeth_card *card) if (card->info.promisc_mode == enable) return; - if (qeth_adp_supported(card, IPA_SETADP_SET_PROMISC_MODE)) + if (qeth_adp_supported(card, IPA_SETADP_SET_PROMISC_MODE)) { qeth_setadp_promisc_mode(card, enable); - else if (card->options.sbp.reflect_promisc) - qeth_l2_promisc_to_bridge(card, enable); + } else { + mutex_lock(&card->sbp_lock); + if (card->options.sbp.reflect_promisc) + qeth_l2_promisc_to_bridge(card, enable); + mutex_unlock(&card->sbp_lock); + } } /* New MAC address is added to the hash table and marked to be written on card @@ -631,6 +635,7 @@ static int qeth_l2_probe_device(struct ccwgroup_device *gdev) int rc; qeth_l2_vnicc_set_defaults(card); + mutex_init(&card->sbp_lock); if (gdev->dev.type == &qeth_generic_devtype) { rc = qeth_l2_create_device_attributes(&gdev->dev); @@ -804,10 +809,12 @@ static int qeth_l2_set_online(struct ccwgroup_device *gdev) } else card->info.hwtrap = 0; + mutex_lock(&card->sbp_lock); qeth_bridgeport_query_support(card); if (card->options.sbp.supported_funcs) dev_info(&card->gdev->dev, "The device represents a Bridge Capable Port\n"); + mutex_unlock(&card->sbp_lock); qeth_l2_register_dev_addr(card); @@ -1162,9 +1169,9 @@ static void qeth_bridge_state_change_worker(struct work_struct *work) /* Role should not change by itself, but if it did, */ /* information from the hardware is authoritative. */ - mutex_lock(&data->card->conf_mutex); + mutex_lock(&data->card->sbp_lock); data->card->options.sbp.role = entry->role; - mutex_unlock(&data->card->conf_mutex); + mutex_unlock(&data->card->sbp_lock); snprintf(env_locrem, sizeof(env_locrem), "BRIDGEPORT=statechange"); snprintf(env_role, sizeof(env_role), "ROLE=%s", @@ -1230,9 +1237,9 @@ static void qeth_bridge_host_event_worker(struct work_struct *work) : (data->hostevs.lost_event_mask == 0x02) ? "Bridge port state change" : "Unknown reason"); - mutex_lock(&data->card->conf_mutex); + mutex_lock(&data->card->sbp_lock); data->card->options.sbp.hostnotification = 0; - mutex_unlock(&data->card->conf_mutex); + mutex_unlock(&data->card->sbp_lock); qeth_bridge_emit_host_event(data->card, anev_abort, 0, NULL, NULL); } else diff --git a/drivers/s390/net/qeth_l2_sys.c b/drivers/s390/net/qeth_l2_sys.c index f2c3b127b1e4..e2bcb26105a3 100644 --- a/drivers/s390/net/qeth_l2_sys.c +++ b/drivers/s390/net/qeth_l2_sys.c @@ -24,6 +24,7 @@ static ssize_t qeth_bridge_port_role_state_show(struct device *dev, if (qeth_l2_vnicc_is_in_use(card)) return sprintf(buf, "n/a (VNIC characteristics)\n"); + mutex_lock(&card->sbp_lock); if (qeth_card_hw_is_reachable(card) && card->options.sbp.supported_funcs) rc = qeth_bridgeport_query_ports(card, @@ -57,6 +58,7 @@ static ssize_t qeth_bridge_port_role_state_show(struct device *dev, else rc = sprintf(buf, "%s\n", word); } + mutex_unlock(&card->sbp_lock); return rc; } @@ -91,6 +93,7 @@ static ssize_t qeth_bridge_port_role_store(struct device *dev, return -EINVAL; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -104,6 +107,7 @@ static ssize_t qeth_bridge_port_role_store(struct device *dev, } else card->options.sbp.role = role; + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -158,6 +162,7 @@ static ssize_t qeth_bridgeport_hostnotification_store(struct device *dev, return rc; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -168,6 +173,7 @@ static ssize_t qeth_bridgeport_hostnotification_store(struct device *dev, } else card->options.sbp.hostnotification = enable; + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -223,6 +229,7 @@ static ssize_t qeth_bridgeport_reflect_store(struct device *dev, return -EINVAL; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -234,6 +241,7 @@ static ssize_t qeth_bridgeport_reflect_store(struct device *dev, rc = 0; } + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -269,6 +277,8 @@ void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card) return; if (!card->options.sbp.supported_funcs) return; + + mutex_lock(&card->sbp_lock); if (card->options.sbp.role != QETH_SBP_ROLE_NONE) { /* Conditional to avoid spurious error messages */ qeth_bridgeport_setrole(card, card->options.sbp.role); @@ -280,8 +290,10 @@ void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card) rc = qeth_bridgeport_an_set(card, 1); if (rc) card->options.sbp.hostnotification = 0; - } else + } else { qeth_bridgeport_an_set(card, 0); + } + mutex_unlock(&card->sbp_lock); } /* VNIC CHARS support */