From patchwork Thu May 17 17:15:05 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steffen Maier X-Patchwork-Id: 10407313 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 302CC602C2 for ; Thu, 17 May 2018 17:16:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1DE8128592 for ; Thu, 17 May 2018 17:16:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 12596285E2; Thu, 17 May 2018 17:16:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9FE4B28592 for ; Thu, 17 May 2018 17:16:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752416AbeEQRQ2 (ORCPT ); Thu, 17 May 2018 13:16:28 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41314 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752385AbeEQRQZ (ORCPT ); Thu, 17 May 2018 13:16:25 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w4HHEOY2029840 for ; Thu, 17 May 2018 13:16:24 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0b-001b2d01.pphosted.com with ESMTP id 2j1d0yavcx-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 17 May 2018 13:16:23 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 17 May 2018 18:16:19 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w4HHGIqA4915528; Thu, 17 May 2018 17:16:18 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 452664C04E; Thu, 17 May 2018 18:08:07 +0100 (BST) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E8BE94C04A; Thu, 17 May 2018 18:08:06 +0100 (BST) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Thu, 17 May 2018 18:08:06 +0100 (BST) From: Steffen Maier To: "James E . J . Bottomley" , "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, linux-s390@vger.kernel.org, Benjamin Block , Martin Schwidefsky , Heiko Carstens , Steffen Maier , Jens Remus Subject: [PATCH 23/25] zfcp: assert that the ERP lock is held when tracing a recovery trigger Date: Thu, 17 May 2018 19:15:05 +0200 X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180517171507.18237-1-maier@linux.ibm.com> References: <20180517171507.18237-1-maier@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18051717-0040-0000-0000-0000043AF016 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18051717-0041-0000-0000-000026400E94 Message-Id: <20180517171507.18237-24-maier@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-05-17_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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805170161 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jens Remus Otherwise iterating with list_for_each() over the adapter->erp_ready_head and adapter->erp_running_head lists can lead to an infinite loop. See commit "zfcp: fix infinite iteration on erp_ready_head list". The run-time check is only performed for debug kernels which have the kernel lock validator enabled. Following is an example of the warning that is reported, if the ERP lock is not held when calling zfcp_dbf_rec_trig(): WARNING: CPU: 0 PID: 604 at drivers/s390/scsi/zfcp_dbf.c:288 zfcp_dbf_rec_trig+0x172/0x188 Modules linked in: ... CPU: 0 PID: 604 Comm: kworker/u128:3 Not tainted 4.16.0-... #1 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) Workqueue: zfcp_q_0.0.1906 zfcp_scsi_rport_work Krnl PSW : 00000000330fdbf9 00000000367e9728 (zfcp_dbf_rec_trig+0x172/0x188) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 Krnl GPRS: 00000000c57a5d99 3288200000000000 0000000000000000 000000006cc82740 00000000009d09d6 0000000000000000 00000000000000ff 0000000000000000 0000000000000000 0000000000e1b5fe 000000006de01d38 0000000076130958 000000006cc82548 000000006de01a98 00000000009d09d6 000000006a6d3c80 Krnl Code: 00000000009d0ad2: eb7ff0b80004 lmg %r7,%r15,184(%r15) 00000000009d0ad8: c0f4000d7dd0 brcl 15,b80678 #00000000009d0ade: a7f40001 brc 15,9d0ae0 >00000000009d0ae2: a7f4ff7d brc 15,9d09dc 00000000009d0ae6: e340f0f00004 lg %r4,240(%r15) 00000000009d0aec: eb7ff0b80004 lmg %r7,%r15,184(%r15) 00000000009d0af2: 07f4 bcr 15,%r4 00000000009d0af4: 0707 bcr 0,%r7 Call Trace: ([<00000000009d09d6>] zfcp_dbf_rec_trig+0x66/0x188) [<00000000009dd740>] zfcp_scsi_rport_work+0x98/0x190 [<0000000000169b34>] process_one_work+0x3d4/0x6f8 [<000000000016a08a>] worker_thread+0x232/0x418 [<000000000017219e>] kthread+0x166/0x178 [<0000000000b815ea>] kernel_thread_starter+0x6/0xc [<0000000000b815e4>] kernel_thread_starter+0x0/0xc 2 locks held by kworker/u128:3/604: #0: ((wq_completion)name){+.+.}, at: [<0000000082af1024>] process_one_work+0x1dc/0x6f8 #1: ((work_completion)(&port->rport_work)){+.+.}, at: [<0000000082af1024>] process_one_work+0x1dc/0x6f8 Last Breaking-Event-Address: [<00000000009d0ade>] zfcp_dbf_rec_trig+0x16e/0x188 ---[ end trace b2f4020572e2c124 ]--- Suggested-by: Steffen Maier Signed-off-by: Jens Remus Reviewed-by: Benjamin Block Reviewed-by: Steffen Maier Signed-off-by: Steffen Maier --- drivers/s390/scsi/zfcp_dbf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c index bb3373260169..781141bf2c28 100644 --- a/drivers/s390/scsi/zfcp_dbf.c +++ b/drivers/s390/scsi/zfcp_dbf.c @@ -285,6 +285,8 @@ void zfcp_dbf_rec_trig(char *tag, struct zfcp_adapter *adapter, struct list_head *entry; unsigned long flags; + lockdep_assert_held(&adapter->erp_lock); + if (unlikely(!debug_level_enabled(dbf->rec, level))) return;