From patchwork Thu Jan 7 17:24:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julian Wiedmann X-Patchwork-Id: 12004547 X-Patchwork-Delegate: kuba@kernel.org 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 6DA6FC433E0 for ; Thu, 7 Jan 2021 17:26:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3786E233FB for ; Thu, 7 Jan 2021 17:26:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728821AbhAGRZg (ORCPT ); Thu, 7 Jan 2021 12:25:36 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:18098 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbhAGRZf (ORCPT ); Thu, 7 Jan 2021 12:25:35 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 107H8Q9j070234; Thu, 7 Jan 2021 12:24:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=pp1; bh=nu+iCIxZqpDQixbz46F0mQ0XZEjJ+oYcs3e+C2barFM=; b=AP665q7rWyfs5PI18P82xALZvRFee7p6ZVNzPCB9HradaI3zjUKWjGTNAxbGIF2hQVsU wlnX9vl6bs1BWCLVY2fvuGNVlj3f6ZOcvSRdwHrvvMCMwBs0UvPE7yVfU4ovOt8XVBK8 U/wmAsGTmjNLaG7QdRWfAbjyGQXJPZoJKHb/72oMPvZ98VsBUxH53gJW9pgnrhZIS1ve ou3fhM1f64wBQCh/ShI+gXf15dOcSrCzKDuTNCnhQJI/OE6tK+jAsYio6MfHfDZzzLZW Yv3aRBEehh3ANGaksAXHOprVmNUYNZkwvu1Vg+OxrvMj/6OjI53kXbIhNaWFyg2q6mxh lg== Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com with ESMTP id 35x5juhxg9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Jan 2021 12:24:53 -0500 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 107HBncT027409; Thu, 7 Jan 2021 17:24:51 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma06ams.nl.ibm.com with ESMTP id 35tg3hd3f1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Jan 2021 17:24:51 +0000 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 107HOmxB37814642 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 7 Jan 2021 17:24:48 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6B44142041; Thu, 7 Jan 2021 17:24:48 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2488C4203F; Thu, 7 Jan 2021 17:24:48 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 7 Jan 2021 17:24:48 +0000 (GMT) From: Julian Wiedmann To: David Miller , Jakub Kicinski Cc: linux-netdev , linux-s390 , Heiko Carstens , Karsten Graul , Julian Wiedmann Subject: [PATCH net 2/3] s390/qeth: fix locking for discipline setup / removal Date: Thu, 7 Jan 2021 18:24:41 +0100 Message-Id: <20210107172442.1737-3-jwi@linux.ibm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210107172442.1737-1-jwi@linux.ibm.com> References: <20210107172442.1737-1-jwi@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343,18.0.737 definitions=2021-01-07_07:2021-01-07,2021-01-07 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 malwarescore=0 impostorscore=0 spamscore=0 adultscore=0 phishscore=0 suspectscore=0 bulkscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101070100 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Due to insufficient locking, qeth_core_set_online() and qeth_dev_layer2_store() can run in parallel, both attempting to load & setup the discipline (and stepping on each other toes along the way). A similar race can also occur between qeth_core_remove_device() and qeth_dev_layer2_store(). Access to .discipline is meant to be protected by the discipline_mutex, so add/expand the locking in qeth_core_remove_device() and qeth_core_set_online(). Adjust the locking in qeth_l*_remove_device() accordingly, as it's now handled by the callers in a consistent manner. Based on an initial patch by Ursula Braun. Fixes: 9dc48ccc68b9 ("qeth: serialize sysfs-triggered device configurations") Signed-off-by: Julian Wiedmann Reviewed-by: Alexandra Winter --- drivers/s390/net/qeth_core_main.c | 7 +++++-- drivers/s390/net/qeth_l2_main.c | 5 +---- drivers/s390/net/qeth_l3_main.c | 5 +---- 3 files changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index d45e223fc521..cf18d87da41e 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -6585,6 +6585,7 @@ static int qeth_core_probe_device(struct ccwgroup_device *gdev) break; default: card->info.layer_enforced = true; + /* It's so early that we don't need the discipline_mutex yet. */ rc = qeth_core_load_discipline(card, enforced_disc); if (rc) goto err_load; @@ -6617,10 +6618,12 @@ static void qeth_core_remove_device(struct ccwgroup_device *gdev) QETH_CARD_TEXT(card, 2, "removedv"); + mutex_lock(&card->discipline_mutex); if (card->discipline) { card->discipline->remove(gdev); qeth_core_free_discipline(card); } + mutex_unlock(&card->discipline_mutex); qeth_free_qdio_queues(card); @@ -6635,6 +6638,7 @@ static int qeth_core_set_online(struct ccwgroup_device *gdev) int rc = 0; enum qeth_discipline_id def_discipline; + mutex_lock(&card->discipline_mutex); if (!card->discipline) { def_discipline = IS_IQD(card) ? QETH_DISCIPLINE_LAYER3 : QETH_DISCIPLINE_LAYER2; @@ -6648,11 +6652,10 @@ static int qeth_core_set_online(struct ccwgroup_device *gdev) } } - mutex_lock(&card->discipline_mutex); rc = qeth_set_online(card, card->discipline); - mutex_unlock(&card->discipline_mutex); err: + mutex_unlock(&card->discipline_mutex); return rc; } diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 37279b1e29f6..4254caf1d9b6 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -2207,11 +2207,8 @@ static void qeth_l2_remove_device(struct ccwgroup_device *gdev) qeth_set_allowed_threads(card, 0, 1); wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0); - if (gdev->state == CCWGROUP_ONLINE) { - mutex_lock(&card->discipline_mutex); + if (gdev->state == CCWGROUP_ONLINE) qeth_set_offline(card, card->discipline, false); - mutex_unlock(&card->discipline_mutex); - } cancel_work_sync(&card->close_dev_work); if (card->dev->reg_state == NETREG_REGISTERED) diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index 8d474179ce98..6970597bc885 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -1970,11 +1970,8 @@ static void qeth_l3_remove_device(struct ccwgroup_device *cgdev) qeth_set_allowed_threads(card, 0, 1); wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0); - if (cgdev->state == CCWGROUP_ONLINE) { - mutex_lock(&card->discipline_mutex); + if (cgdev->state == CCWGROUP_ONLINE) qeth_set_offline(card, card->discipline, false); - mutex_unlock(&card->discipline_mutex); - } cancel_work_sync(&card->close_dev_work); if (card->dev->reg_state == NETREG_REGISTERED)