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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 7219CC31E40 for ; Mon, 12 Aug 2019 14:44:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A5C4206A2 for ; Mon, 12 Aug 2019 14:44:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726864AbfHLOor (ORCPT ); Mon, 12 Aug 2019 10:44:47 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:15782 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726585AbfHLOor (ORCPT ); Mon, 12 Aug 2019 10:44:47 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x7CEgteb006468 for ; Mon, 12 Aug 2019 10:44:45 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ub7tseh8r-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 12 Aug 2019 10:44:45 -0400 Received: from localhost by e06smtp05.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) Mon, 12 Aug 2019 15:44:40 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7CEidpp14745842 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 12 Aug 2019 14:44:39 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0E9A44203F; Mon, 12 Aug 2019 14:44:39 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C48CD42049; Mon, 12 Aug 2019 14:44:38 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 12 Aug 2019 14:44:38 +0000 (GMT) From: Julian Wiedmann To: David Miller Cc: , , Heiko Carstens , Stefan Raspl , Ursula Braun , Julian Wiedmann Subject: [PATCH net] s390/qeth: serialize cmd reply with concurrent timeout Date: Mon, 12 Aug 2019 16:44:35 +0200 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 19081214-0020-0000-0000-0000035EDBF1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19081214-0021-0000-0000-000021B3EBB1 Message-Id: <20190812144435.67451-1-jwi@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-12_06:,, 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=789 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908120165 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Callbacks for a cmd reply run outside the protection of card->lock, to allow for additional cmds to be issued & enqueued in parallel. When qeth_send_control_data() bails out for a cmd without having received a reply (eg. due to timeout), its callback may concurrently be processing a reply that just arrived. In this case, the callback potentially accesses a stale reply->reply_param area that eg. was on-stack and has already been released. To avoid this race, add some locking so that qeth_send_control_data() can (1) wait for a concurrently running callback, and (2) zap any pending callback that still wants to run. Signed-off-by: Julian Wiedmann --- drivers/s390/net/qeth_core.h | 1 + drivers/s390/net/qeth_core_main.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index c7ee07ce3615..28db887d38ed 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -629,6 +629,7 @@ struct qeth_seqno { struct qeth_reply { struct list_head list; struct completion received; + spinlock_t lock; int (*callback)(struct qeth_card *, struct qeth_reply *, unsigned long); u32 seqno; diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 4d0caeebc802..9c3310c4d61d 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -544,6 +544,7 @@ static struct qeth_reply *qeth_alloc_reply(struct qeth_card *card) if (reply) { refcount_set(&reply->refcnt, 1); init_completion(&reply->received); + spin_lock_init(&reply->lock); } return reply; } @@ -799,6 +800,13 @@ static void qeth_issue_next_read_cb(struct qeth_card *card, if (!reply->callback) { rc = 0; + goto no_callback; + } + + spin_lock_irqsave(&reply->lock, flags); + if (reply->rc) { + /* Bail out when the requestor has already left: */ + rc = reply->rc; } else { if (cmd) { reply->offset = (u16)((char *)cmd - (char *)iob->data); @@ -807,7 +815,9 @@ static void qeth_issue_next_read_cb(struct qeth_card *card, rc = reply->callback(card, reply, (unsigned long)iob); } } + spin_unlock_irqrestore(&reply->lock, flags); +no_callback: if (rc <= 0) qeth_notify_reply(reply, rc); qeth_put_reply(reply); @@ -1749,6 +1759,16 @@ static int qeth_send_control_data(struct qeth_card *card, rc = (timeout == -ERESTARTSYS) ? -EINTR : -ETIME; qeth_dequeue_reply(card, reply); + + if (reply_cb) { + /* Wait until the callback for a late reply has completed: */ + spin_lock_irq(&reply->lock); + if (rc) + /* Zap any callback that's still pending: */ + reply->rc = rc; + spin_unlock_irq(&reply->lock); + } + if (!rc) rc = reply->rc; qeth_put_reply(reply); -- 2.17.1