From patchwork Fri May 19 12:06:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 9737037 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 6A84D601A1 for ; Fri, 19 May 2017 12:06:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 55B6928911 for ; Fri, 19 May 2017 12:06:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 49F1F28916; Fri, 19 May 2017 12:06:56 +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=-6.9 required=2.0 tests=BAYES_00,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 C367428896 for ; Fri, 19 May 2017 12:06:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750857AbdESMGc (ORCPT ); Fri, 19 May 2017 08:06:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36218 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814AbdESMGb (ORCPT ); Fri, 19 May 2017 08:06:31 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D535EC0567A3; Fri, 19 May 2017 12:06:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D535EC0567A3 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=asavkov@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com D535EC0567A3 Received: from shodan.usersys.redhat.com (dhcp-1-119.brq.redhat.com [10.34.1.119]) by smtp.corp.redhat.com (Postfix) with ESMTP id 781257EBF0; Fri, 19 May 2017 12:06:29 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id A55302C601E; Fri, 19 May 2017 14:06:28 +0200 (CEST) From: Artem Savkov To: hare@suse.de Cc: axboe@fb.com, hch@lst.de, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Artem Savkov Subject: [PATCH] Use ctlr directly in rdac_failover_get() Date: Fri, 19 May 2017 14:06:14 +0200 Message-Id: <1495195574-27835-1-git-send-email-asavkov@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 19 May 2017 12:06:30 +0000 (UTC) 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 rdac_failover_get references struct rdac_controller as ctlr->ms_sdev->handler_data->ctlr for no apparent reason. Besides being inefficient this also introduces a null-pointer dereference as send_mode_select() sets ctlr->ms_sdev to NULL before calling rdac_failover_get(): [ 18.432550] device-mapper: multipath service-time: version 0.3.0 loaded [ 18.436124] BUG: unable to handle kernel NULL pointer dereference at 0000000000000790 [ 18.436129] IP: send_mode_select+0xca/0x560 [ 18.436129] PGD 0 [ 18.436130] P4D 0 [ 18.436130] [ 18.436132] Oops: 0000 [#1] SMP [ 18.436133] Modules linked in: dm_service_time sd_mod dm_multipath amdkfd amd_iommu_v2 radeon(+) i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm qla2xxx drm serio_raw scsi_transport_fc bnx2 i2c_core dm_mirror dm_region_hash dm_log dm_mod [ 18.436143] CPU: 4 PID: 443 Comm: kworker/u16:2 Not tainted 4.12.0-rc1.1.el7.test.x86_64 #1 [ 18.436144] Hardware name: IBM BladeCenter LS22 -[79013SG]-/Server Blade, BIOS -[L8E164AUS-1.07]- 05/25/2011 [ 18.436145] Workqueue: kmpath_rdacd send_mode_select [ 18.436146] task: ffff880225116a40 task.stack: ffffc90002bd8000 [ 18.436148] RIP: 0010:send_mode_select+0xca/0x560 [ 18.436148] RSP: 0018:ffffc90002bdbda8 EFLAGS: 00010246 [ 18.436149] RAX: 0000000000000000 RBX: ffffc90002bdbe08 RCX: ffff88017ef04a80 [ 18.436150] RDX: ffffc90002bdbe08 RSI: ffff88017ef04a80 RDI: ffff8802248e4388 [ 18.436151] RBP: ffffc90002bdbe48 R08: 0000000000000000 R09: ffffffff81c104c0 [ 18.436151] R10: 00000000000001ff R11: 000000000000035a R12: ffffc90002bdbdd8 [ 18.436152] R13: ffff8802248e4390 R14: ffff880225152800 R15: ffff8802248e4400 [ 18.436153] FS: 0000000000000000(0000) GS:ffff880227d00000(0000) knlGS:0000000000000000 [ 18.436154] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 18.436154] CR2: 0000000000000790 CR3: 000000042535b000 CR4: 00000000000006e0 [ 18.436155] Call Trace: [ 18.436159] ? rdac_activate+0x14e/0x150 [ 18.436161] ? refcount_dec_and_test+0x11/0x20 [ 18.436162] ? kobject_put+0x1c/0x50 [ 18.436165] ? scsi_dh_activate+0x6f/0xd0 [ 18.436168] process_one_work+0x149/0x360 [ 18.436170] worker_thread+0x4d/0x3c0 [ 18.436172] kthread+0x109/0x140 [ 18.436173] ? rescuer_thread+0x380/0x380 [ 18.436174] ? kthread_park+0x60/0x60 [ 18.436176] ret_from_fork+0x2c/0x40 [ 18.436177] Code: 49 c7 46 20 00 00 00 00 4c 89 ef c6 07 00 0f 1f 40 00 45 31 ed c7 45 b0 05 00 00 00 44 89 6d b4 4d 89 f5 4c 8b 75 a8 49 8b 45 20 <48> 8b b0 90 07 00 00 48 8b 56 10 8b 42 10 48 8d 7a 28 85 c0 0f [ 18.436192] RIP: send_mode_select+0xca/0x560 RSP: ffffc90002bdbda8 [ 18.436192] CR2: 0000000000000790 [ 18.436198] ---[ end trace 40f3e4dca1ffabdd ]--- [ 18.436199] Kernel panic - not syncing: Fatal exception [ 18.436222] Kernel Offset: disabled [-- MARK -- Thu May 18 11:45:00 2017] Signed-off-by: Artem Savkov --- drivers/scsi/device_handler/scsi_dh_rdac.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 3cbab87..2ceff58 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -265,18 +265,16 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, struct list_head *list, unsigned char *cdb) { - struct scsi_device *sdev = ctlr->ms_sdev; - struct rdac_dh_data *h = sdev->handler_data; struct rdac_mode_common *common; unsigned data_size; struct rdac_queue_data *qdata; u8 *lun_table; - if (h->ctlr->use_ms10) { + if (ctlr->use_ms10) { struct rdac_pg_expanded *rdac_pg; data_size = sizeof(struct rdac_pg_expanded); - rdac_pg = &h->ctlr->mode_select.expanded; + rdac_pg = &ctlr->mode_select.expanded; memset(rdac_pg, 0, data_size); common = &rdac_pg->common; rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40; @@ -288,7 +286,7 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, struct rdac_pg_legacy *rdac_pg; data_size = sizeof(struct rdac_pg_legacy); - rdac_pg = &h->ctlr->mode_select.legacy; + rdac_pg = &ctlr->mode_select.legacy; memset(rdac_pg, 0, data_size); common = &rdac_pg->common; rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER; @@ -304,7 +302,7 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, } /* Prepare the command. */ - if (h->ctlr->use_ms10) { + if (ctlr->use_ms10) { cdb[0] = MODE_SELECT_10; cdb[7] = data_size >> 8; cdb[8] = data_size & 0xff;