From patchwork Mon Dec 21 02:37:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 346542 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY,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 31ECFC43381 for ; Mon, 21 Dec 2020 02:38:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E395D22DCC for ; Mon, 21 Dec 2020 02:38:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727473AbgLUCij (ORCPT ); Sun, 20 Dec 2020 21:38:39 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:39582 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726550AbgLUCij (ORCPT ); Sun, 20 Dec 2020 21:38:39 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0BL2UXk6087182; Mon, 21 Dec 2020 02:37:30 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=en2bC/k43AcT8h+BAvgClxxzHM7PR0o20i6Gzh84QGE=; b=cdZ4sWj08h7Gyt5o6PiV61dMt89XEs2Sekd/CXFJz+EX3/h3NbfCNM+eLv2hZxi0T4b4 MpSgAtJ2s638YvEuuA9zbQnS11wYEnioHgNTybv5tMLFV5Z/Qu9hY/WuY71ggns2L0HS EaIFUpfwuvGOK7rF8Dm0Gk2tafEcS28xK7CFnzEQg870kZZdReLPB/Zr2PP6SuuthEqW XrGOuhoH5sHiBGSK+u/rBtBAWpXeFzETJ2NLhrst0f/+83B1czN9XYeI+83MnIVuOQbw XUwsKQTko4jCvKk5cczK0dpMET6sxmbLSyhKoVWHJ3aa2h9miY6Ohk8u+1JCtZT2csuz VQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 35h8xquaue-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 21 Dec 2020 02:37:30 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0BL2aR92119441; Mon, 21 Dec 2020 02:37:29 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 35huev06eh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 21 Dec 2020 02:37:29 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0BL2bO5V009308; Mon, 21 Dec 2020 02:37:26 GMT Received: from ol2.localdomain (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 20 Dec 2020 18:37:24 -0800 From: Mike Christie To: lduncan@suse.com, cleech@redhat.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, james.bottomley@hansenpartnership.com Cc: lutianxiong@huawei.com, linfeilong@huawei.com, liuzhiqiang26@huawei.com, haowenchao@huawei.com Subject: [PATCH 2/6 V3] libiscsi: drop taskqueuelock Date: Sun, 20 Dec 2020 20:37:02 -0600 Message-Id: <1608518226-30376-3-git-send-email-michael.christie@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1608518226-30376-1-git-send-email-michael.christie@oracle.com> References: <1608518226-30376-1-git-send-email-michael.christie@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9841 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxscore=0 spamscore=0 mlxlogscore=999 malwarescore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012210018 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9841 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 clxscore=1015 priorityscore=1501 mlxscore=0 lowpriorityscore=0 adultscore=0 mlxlogscore=999 suspectscore=0 phishscore=0 impostorscore=0 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012210017 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org The purpose of the taskqueuelock was to handle the issue where a bad target decides to send a R2T and before it's data has been sent decides to send a cmd response to complete the cmd. The following patches fix up the frwd/back locks so they are taken from the queue/xmit (frwd) and completion (back) paths again. To get there this patch removes the taskqueuelock which for iscsi xmit wq based drivers was taken in the queue, xmit and completion paths. Instead of the lock, we just make sure we have a ref to the task when we queue a R2T, and then we always remove the task from the requeue list in the xmit path or the forced cleanup paths. Signed-off-by: Mike Christie Reviewed-by: Lee Duncan --- drivers/scsi/libiscsi.c | 178 ++++++++++++++++++++++++++++---------------- drivers/scsi/libiscsi_tcp.c | 84 ++++++++++++++------- include/scsi/libiscsi.h | 4 +- 3 files changed, 171 insertions(+), 95 deletions(-) diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index ee0786b..5582e4f 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -523,16 +523,6 @@ static void iscsi_complete_task(struct iscsi_task *task, int state) WARN_ON_ONCE(task->state == ISCSI_TASK_FREE); task->state = state; - spin_lock_bh(&conn->taskqueuelock); - if (!list_empty(&task->running)) { - pr_debug_once("%s while task on list", __func__); - list_del_init(&task->running); - } - spin_unlock_bh(&conn->taskqueuelock); - - if (conn->task == task) - conn->task = NULL; - if (READ_ONCE(conn->ping_task) == task) WRITE_ONCE(conn->ping_task, NULL); @@ -564,9 +554,40 @@ void iscsi_complete_scsi_task(struct iscsi_task *task, } EXPORT_SYMBOL_GPL(iscsi_complete_scsi_task); +/* + * Must be called with back and frwd lock + */ +static bool cleanup_queued_task(struct iscsi_task *task) +{ + struct iscsi_conn *conn = task->conn; + bool early_complete = false; + + /* Bad target might have completed task while it was still running */ + if (task->state == ISCSI_TASK_COMPLETED) + early_complete = true; + + if (!list_empty(&task->running)) { + list_del_init(&task->running); + /* + * If it's on a list but still running, this could be from + * a bad target sending a rsp early, cleanup from a TMF, or + * session recovery. + */ + if (task->state == ISCSI_TASK_RUNNING || + task->state == ISCSI_TASK_COMPLETED) + __iscsi_put_task(task); + } + + if (conn->task == task) { + conn->task = NULL; + __iscsi_put_task(task); + } + + return early_complete; +} /* - * session back_lock must be held and if not called for a task that is + * session frwd_lock must be held and if not called for a task that is * still pending or from the xmit thread, then xmit thread must * be suspended. */ @@ -585,6 +606,13 @@ static void fail_scsi_task(struct iscsi_task *task, int err) if (!sc) return; + /* regular RX path uses back_lock */ + spin_lock_bh(&conn->session->back_lock); + if (cleanup_queued_task(task)) { + spin_unlock_bh(&conn->session->back_lock); + return; + } + if (task->state == ISCSI_TASK_PENDING) { /* * cmd never made it to the xmit thread, so we should not count @@ -600,9 +628,6 @@ static void fail_scsi_task(struct iscsi_task *task, int err) sc->result = err << 16; scsi_set_resid(sc, scsi_bufflen(sc)); - - /* regular RX path uses back_lock */ - spin_lock_bh(&conn->session->back_lock); iscsi_complete_task(task, state); spin_unlock_bh(&conn->session->back_lock); } @@ -748,9 +773,7 @@ static int iscsi_prep_mgmt_task(struct iscsi_conn *conn, if (session->tt->xmit_task(task)) goto free_task; } else { - spin_lock_bh(&conn->taskqueuelock); list_add_tail(&task->running, &conn->mgmtqueue); - spin_unlock_bh(&conn->taskqueuelock); iscsi_conn_queue_work(conn); } @@ -1411,31 +1434,61 @@ static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn) return 0; } -static int iscsi_xmit_task(struct iscsi_conn *conn) +static int iscsi_xmit_task(struct iscsi_conn *conn, struct iscsi_task *task, + bool was_requeue) { - struct iscsi_task *task = conn->task; int rc; - if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) - return -ENODATA; - spin_lock_bh(&conn->session->back_lock); - if (conn->task == NULL) { + + if (!conn->task) { + /* Take a ref so we can access it after xmit_task() */ + __iscsi_get_task(task); + } else { + /* Already have a ref from when we failed to send it last call */ + conn->task = NULL; + } + + /* + * If this was a requeue for a R2T we have an extra ref on the task in + * case a bad target sends a cmd rsp before we have handled the task. + */ + if (was_requeue) + __iscsi_put_task(task); + + /* + * Do this after dropping the extra ref because if this was a requeue + * it's removed from that list and cleanup_queued_task would miss it. + */ + if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) { + /* + * Save the task and ref in case we weren't cleaning up this + * task and get woken up again. + */ + conn->task = task; spin_unlock_bh(&conn->session->back_lock); return -ENODATA; } - __iscsi_get_task(task); spin_unlock_bh(&conn->session->back_lock); + spin_unlock_bh(&conn->session->frwd_lock); rc = conn->session->tt->xmit_task(task); spin_lock_bh(&conn->session->frwd_lock); if (!rc) { /* done with this task */ task->last_xfer = jiffies; - conn->task = NULL; } /* regular RX path uses back_lock */ spin_lock(&conn->session->back_lock); + if (rc && task->state == ISCSI_TASK_RUNNING) { + /* + * get an extra ref that is released next time we access it + * as conn->task above. + */ + __iscsi_get_task(task); + conn->task = task; + } + __iscsi_put_task(task); spin_unlock(&conn->session->back_lock); return rc; @@ -1445,9 +1498,7 @@ static int iscsi_xmit_task(struct iscsi_conn *conn) * iscsi_requeue_task - requeue task to run from session workqueue * @task: task to requeue * - * LLDs that need to run a task from the session workqueue should call - * this. The session frwd_lock must be held. This should only be called - * by software drivers. + * Callers must have taken a ref to the task that is going to be requeued. */ void iscsi_requeue_task(struct iscsi_task *task) { @@ -1457,11 +1508,18 @@ void iscsi_requeue_task(struct iscsi_task *task) * this may be on the requeue list already if the xmit_task callout * is handling the r2ts while we are adding new ones */ - spin_lock_bh(&conn->taskqueuelock); - if (list_empty(&task->running)) + spin_lock_bh(&conn->session->frwd_lock); + if (list_empty(&task->running)) { list_add_tail(&task->running, &conn->requeue); - spin_unlock_bh(&conn->taskqueuelock); + } else { + /* + * Don't need the extra ref since it's already requeued and + * has a ref. + */ + iscsi_put_task(task); + } iscsi_conn_queue_work(conn); + spin_unlock_bh(&conn->session->frwd_lock); } EXPORT_SYMBOL_GPL(iscsi_requeue_task); @@ -1487,7 +1545,7 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) } if (conn->task) { - rc = iscsi_xmit_task(conn); + rc = iscsi_xmit_task(conn, conn->task, false); if (rc) goto done; } @@ -1497,49 +1555,41 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) * only have one nop-out as a ping from us and targets should not * overflow us with nop-ins */ - spin_lock_bh(&conn->taskqueuelock); check_mgmt: while (!list_empty(&conn->mgmtqueue)) { - conn->task = list_entry(conn->mgmtqueue.next, - struct iscsi_task, running); - list_del_init(&conn->task->running); - spin_unlock_bh(&conn->taskqueuelock); - if (iscsi_prep_mgmt_task(conn, conn->task)) { + task = list_entry(conn->mgmtqueue.next, struct iscsi_task, + running); + list_del_init(&task->running); + if (iscsi_prep_mgmt_task(conn, task)) { /* regular RX path uses back_lock */ spin_lock_bh(&conn->session->back_lock); - __iscsi_put_task(conn->task); + __iscsi_put_task(task); spin_unlock_bh(&conn->session->back_lock); - conn->task = NULL; - spin_lock_bh(&conn->taskqueuelock); continue; } - rc = iscsi_xmit_task(conn); + rc = iscsi_xmit_task(conn, task, false); if (rc) goto done; - spin_lock_bh(&conn->taskqueuelock); } /* process pending command queue */ while (!list_empty(&conn->cmdqueue)) { - conn->task = list_entry(conn->cmdqueue.next, struct iscsi_task, - running); - list_del_init(&conn->task->running); - spin_unlock_bh(&conn->taskqueuelock); + task = list_entry(conn->cmdqueue.next, struct iscsi_task, + running); + list_del_init(&task->running); if (conn->session->state == ISCSI_STATE_LOGGING_OUT) { - fail_scsi_task(conn->task, DID_IMM_RETRY); - spin_lock_bh(&conn->taskqueuelock); + fail_scsi_task(task, DID_IMM_RETRY); continue; } - rc = iscsi_prep_scsi_cmd_pdu(conn->task); + rc = iscsi_prep_scsi_cmd_pdu(task); if (rc) { if (rc == -ENOMEM || rc == -EACCES) - fail_scsi_task(conn->task, DID_IMM_RETRY); + fail_scsi_task(task, DID_IMM_RETRY); else - fail_scsi_task(conn->task, DID_ABORT); - spin_lock_bh(&conn->taskqueuelock); + fail_scsi_task(task, DID_ABORT); continue; } - rc = iscsi_xmit_task(conn); + rc = iscsi_xmit_task(conn, task, false); if (rc) goto done; /* @@ -1547,7 +1597,6 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) * we need to check the mgmt queue for nops that need to * be sent to aviod starvation */ - spin_lock_bh(&conn->taskqueuelock); if (!list_empty(&conn->mgmtqueue)) goto check_mgmt; } @@ -1561,21 +1610,17 @@ static int iscsi_data_xmit(struct iscsi_conn *conn) task = list_entry(conn->requeue.next, struct iscsi_task, running); + if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT)) break; - conn->task = task; - list_del_init(&conn->task->running); - conn->task->state = ISCSI_TASK_RUNNING; - spin_unlock_bh(&conn->taskqueuelock); - rc = iscsi_xmit_task(conn); + list_del_init(&task->running); + rc = iscsi_xmit_task(conn, task, true); if (rc) goto done; - spin_lock_bh(&conn->taskqueuelock); if (!list_empty(&conn->mgmtqueue)) goto check_mgmt; } - spin_unlock_bh(&conn->taskqueuelock); spin_unlock_bh(&conn->session->frwd_lock); return -ENODATA; @@ -1741,9 +1786,7 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc) goto prepd_reject; } } else { - spin_lock_bh(&conn->taskqueuelock); list_add_tail(&task->running, &conn->cmdqueue); - spin_unlock_bh(&conn->taskqueuelock); iscsi_conn_queue_work(conn); } @@ -2914,7 +2957,6 @@ struct iscsi_cls_conn * INIT_LIST_HEAD(&conn->mgmtqueue); INIT_LIST_HEAD(&conn->cmdqueue); INIT_LIST_HEAD(&conn->requeue); - spin_lock_init(&conn->taskqueuelock); INIT_WORK(&conn->xmitwork, iscsi_xmitworker); /* allocate login_task used for the login/text sequences */ @@ -3080,10 +3122,16 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn) ISCSI_DBG_SESSION(conn->session, "failing mgmt itt 0x%x state %d\n", task->itt, task->state); + + spin_lock_bh(&session->back_lock); + if (cleanup_queued_task(task)) { + spin_unlock_bh(&session->back_lock); + continue; + } + state = ISCSI_TASK_ABRT_SESS_RECOV; if (task->state == ISCSI_TASK_PENDING) state = ISCSI_TASK_COMPLETED; - spin_lock_bh(&session->back_lock); iscsi_complete_task(task, state); spin_unlock_bh(&session->back_lock); } diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c index 83f14b2..14c9169 100644 --- a/drivers/scsi/libiscsi_tcp.c +++ b/drivers/scsi/libiscsi_tcp.c @@ -524,48 +524,79 @@ static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task) /** * iscsi_tcp_r2t_rsp - iSCSI R2T Response processing * @conn: iscsi connection - * @task: scsi command task + * @hdr: PDU header */ -static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) +static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr) { struct iscsi_session *session = conn->session; - struct iscsi_tcp_task *tcp_task = task->dd_data; - struct iscsi_tcp_conn *tcp_conn = conn->dd_data; - struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr; + struct iscsi_tcp_task *tcp_task; + struct iscsi_tcp_conn *tcp_conn; + struct iscsi_r2t_rsp *rhdr; struct iscsi_r2t_info *r2t; - int r2tsn = be32_to_cpu(rhdr->r2tsn); + struct iscsi_task *task; u32 data_length; u32 data_offset; + int r2tsn; int rc; + spin_lock(&session->back_lock); + task = iscsi_itt_to_ctask(conn, hdr->itt); + if (!task) { + spin_unlock(&session->back_lock); + return ISCSI_ERR_BAD_ITT; + } else if (task->sc->sc_data_direction != DMA_TO_DEVICE) { + spin_unlock(&session->back_lock); + return ISCSI_ERR_PROTO; + } + /* + * A bad target might complete the cmd before we have handled R2Ts + * so get a ref to the task that will be dropped in the xmit path. + */ + if (task->state != ISCSI_TASK_RUNNING) { + spin_unlock(&session->back_lock); + /* Let the path that got the early rsp complete it */ + return 0; + } + task->last_xfer = jiffies; + __iscsi_get_task(task); + + tcp_conn = conn->dd_data; + rhdr = (struct iscsi_r2t_rsp *)tcp_conn->in.hdr; + /* fill-in new R2T associated with the task */ + iscsi_update_cmdsn(session, (struct iscsi_nopin *)rhdr); + spin_unlock(&session->back_lock); + if (tcp_conn->in.datalen) { iscsi_conn_printk(KERN_ERR, conn, "invalid R2t with datalen %d\n", tcp_conn->in.datalen); - return ISCSI_ERR_DATALEN; + rc = ISCSI_ERR_DATALEN; + goto put_task; } + tcp_task = task->dd_data; + r2tsn = be32_to_cpu(rhdr->r2tsn); if (tcp_task->exp_datasn != r2tsn){ ISCSI_DBG_TCP(conn, "task->exp_datasn(%d) != rhdr->r2tsn(%d)\n", tcp_task->exp_datasn, r2tsn); - return ISCSI_ERR_R2TSN; + rc = ISCSI_ERR_R2TSN; + goto put_task; } - /* fill-in new R2T associated with the task */ - iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr); - if (!task->sc || session->state != ISCSI_STATE_LOGGED_IN) { iscsi_conn_printk(KERN_INFO, conn, "dropping R2T itt %d in recovery.\n", task->itt); - return 0; + rc = 0; + goto put_task; } data_length = be32_to_cpu(rhdr->data_length); if (data_length == 0) { iscsi_conn_printk(KERN_ERR, conn, "invalid R2T with zero data len\n"); - return ISCSI_ERR_DATALEN; + rc = ISCSI_ERR_DATALEN; + goto put_task; } if (data_length > session->max_burst) @@ -579,7 +610,8 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) "invalid R2T with data len %u at offset %u " "and total length %d\n", data_length, data_offset, task->sc->sdb.length); - return ISCSI_ERR_DATALEN; + rc = ISCSI_ERR_DATALEN; + goto put_task; } spin_lock(&tcp_task->pool2queue); @@ -589,7 +621,8 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) "Target has sent more R2Ts than it " "negotiated for or driver has leaked.\n"); spin_unlock(&tcp_task->pool2queue); - return ISCSI_ERR_PROTO; + rc = ISCSI_ERR_PROTO; + goto put_task; } r2t->exp_statsn = rhdr->statsn; @@ -607,6 +640,10 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) iscsi_requeue_task(task); return 0; + +put_task: + iscsi_put_task(task); + return rc; } /* @@ -730,20 +767,11 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task) rc = iscsi_complete_pdu(conn, hdr, NULL, 0); break; case ISCSI_OP_R2T: - spin_lock(&conn->session->back_lock); - task = iscsi_itt_to_ctask(conn, hdr->itt); - spin_unlock(&conn->session->back_lock); - if (!task) - rc = ISCSI_ERR_BAD_ITT; - else if (ahslen) + if (ahslen) { rc = ISCSI_ERR_AHSLEN; - else if (task->sc->sc_data_direction == DMA_TO_DEVICE) { - task->last_xfer = jiffies; - spin_lock(&conn->session->frwd_lock); - rc = iscsi_tcp_r2t_rsp(conn, task); - spin_unlock(&conn->session->frwd_lock); - } else - rc = ISCSI_ERR_PROTO; + break; + } + rc = iscsi_tcp_r2t_rsp(conn, hdr); break; case ISCSI_OP_LOGIN_RSP: case ISCSI_OP_TEXT_RSP: diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h index b3bbd10..44a9554 100644 --- a/include/scsi/libiscsi.h +++ b/include/scsi/libiscsi.h @@ -187,7 +187,7 @@ struct iscsi_conn { struct iscsi_task *task; /* xmit task in progress */ /* xmit */ - spinlock_t taskqueuelock; /* protects the next three lists */ + /* items must be added/deleted under frwd lock */ struct list_head mgmtqueue; /* mgmt (control) xmit queue */ struct list_head cmdqueue; /* data-path cmd queue */ struct list_head requeue; /* tasks needing another run */ @@ -332,7 +332,7 @@ struct iscsi_session { * cmdsn, queued_cmdsn * * session resources: * * - cmdpool kfifo_out , * - * - mgmtpool, */ + * - mgmtpool, queues */ spinlock_t back_lock; /* protects cmdsn_exp * * cmdsn_max, * * cmdpool kfifo_in */ From patchwork Mon Dec 21 02:37:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 346540 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,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 0BDFDC433E0 for ; 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Mon, 21 Dec 2020 02:39:32 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 0BL2ZRPW055519; Mon, 21 Dec 2020 02:37:31 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 35hu9p8f5f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 21 Dec 2020 02:37:31 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 0BL2bPNr013315; Mon, 21 Dec 2020 02:37:26 GMT Received: from ol2.localdomain (/73.88.28.6) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 20 Dec 2020 18:37:24 -0800 From: Mike Christie To: lduncan@suse.com, cleech@redhat.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, james.bottomley@hansenpartnership.com Cc: lutianxiong@huawei.com, linfeilong@huawei.com, liuzhiqiang26@huawei.com, haowenchao@huawei.com Subject: [PATCH 3/6 V3] libiscsi: fix iscsi_task use after free Date: Sun, 20 Dec 2020 20:37:03 -0600 Message-Id: <1608518226-30376-4-git-send-email-michael.christie@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1608518226-30376-1-git-send-email-michael.christie@oracle.com> References: <1608518226-30376-1-git-send-email-michael.christie@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9841 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 bulkscore=0 malwarescore=0 mlxscore=0 mlxlogscore=999 suspectscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012210018 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9841 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 impostorscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 adultscore=0 clxscore=1015 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012210017 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org The following bug was reported and debugged by wubo40@huawei.com: When testing kernel 4.18 version, NULL pointer dereference problem occurs in iscsi_eh_cmd_timed_out function. I think this bug in the upstream is still exists. The analysis reasons are as follows: 1) For some reason, I/O command did not complete within the timeout period. The block layer timer works, call scsi_times_out() to handle I/O timeout logic. At the same time the command just completes. 2) scsi_times_out() call iscsi_eh_cmd_timed_out() to processing timeout logic. although there is an NULL judgment for the task, the task has not been released yet now. 3) iscsi_complete_task() call __iscsi_put_task(), The task reference count reaches zero, the conditions for free task is met, then iscsi_free_task () free the task, and let sc->SCp.ptr = NULL. After iscsi_eh_cmd_timed_out passes the task judgment check, there may be NULL dereference scenarios later. CPU0 CPU3 |- scsi_times_out() |- iscsi_complete_task() | | |- iscsi_eh_cmd_timed_out() |- __iscsi_put_task() | | |- task=sc->SCp.ptr, task is not NUL, check passed |- iscsi_free_task(task) | | | |-> sc->SCp.ptr = NULL | | |- task is NULL now, NULL pointer dereference | | | \|/ \|/ Calltrace: [380751.840862] BUG: unable to handle kernel NULL pointer dereference at 0000000000000138 [380751.843709] PGD 0 P4D 0 [380751.844770] Oops: 0000 [#1] SMP PTI [380751.846283] CPU: 0 PID: 403 Comm: kworker/0:1H Kdump: loaded Tainted: G [380751.851467] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) [380751.856521] Workqueue: kblockd blk_mq_timeout_work [380751.858527] RIP: 0010:iscsi_eh_cmd_timed_out+0x15e/0x2e0 [libiscsi] [380751.861129] Code: 83 ea 01 48 8d 74 d0 08 48 8b 10 48 8b 4a 50 48 85 c9 74 2c 48 39 d5 74 [380751.868811] RSP: 0018:ffffc1e280a5fd58 EFLAGS: 00010246 [380751.870978] RAX: ffff9fd1e84e15e0 RBX: ffff9fd1e84e6dd0 RCX: 0000000116acc580 [380751.873791] RDX: ffff9fd1f97a9400 RSI: ffff9fd1e84e1800 RDI: ffff9fd1e4d6d420 [380751.876059] RBP: ffff9fd1e4d49000 R08: 0000000116acc580 R09: 0000000116acc580 [380751.878284] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9fd1e6e931e8 [380751.880500] R13: ffff9fd1e84e6ee0 R14: 0000000000000010 R15: 0000000000000003 [380751.882687] FS: 0000000000000000(0000) GS:ffff9fd1fac00000(0000) knlGS:0000000000000000 [380751.885236] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [380751.887059] CR2: 0000000000000138 CR3: 000000011860a001 CR4: 00000000003606f0 [380751.889308] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [380751.891523] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [380751.893738] Call Trace: [380751.894639] scsi_times_out+0x60/0x1c0 [380751.895861] blk_mq_check_expired+0x144/0x200 [380751.897302] ? __switch_to_asm+0x35/0x70 [380751.898551] blk_mq_queue_tag_busy_iter+0x195/0x2e0 [380751.900091] ? __blk_mq_requeue_request+0x100/0x100 [380751.901611] ? __switch_to_asm+0x41/0x70 [380751.902853] ? __blk_mq_requeue_request+0x100/0x100 [380751.904398] blk_mq_timeout_work+0x54/0x130 [380751.905740] process_one_work+0x195/0x390 [380751.907228] worker_thread+0x30/0x390 [380751.908713] ? process_one_work+0x390/0x390 [380751.910350] kthread+0x10d/0x130 [380751.911470] ? kthread_flush_work_fn+0x10/0x10 [380751.913007] ret_from_fork+0x35/0x40 crash> dis -l iscsi_eh_cmd_timed_out+0x15e xxxxx/drivers/scsi/libiscsi.c: 2062 1970 enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) { ... 1984 spin_lock_bh(&session->frwd_lock); 1985 task = (struct iscsi_task *)sc->SCp.ptr; 1986 if (!task) { 1987 /* 1988 * Raced with completion. Blk layer has taken ownership 1989 * so let timeout code complete it now. 1990 */ 1991 rc = BLK_EH_DONE; 1992 goto done; 1993 } ... 2052 for (i = 0; i < conn->session->cmds_max; i++) { 2053 running_task = conn->session->cmds[i]; 2054 if (!running_task->sc || running_task == task || 2055 running_task->state != ISCSI_TASK_RUNNING) 2056 continue; 2057 2058 /* 2059 * Only check if cmds started before this one have made 2060 * progress, or this could never fail 2061 */ 2062 if (time_after(running_task->sc->jiffies_at_alloc, 2063 task->sc->jiffies_at_alloc)) <--- 2064 continue; 2065 ... } carsh> struct scsi_cmnd ffff9fd1e6e931e8 struct scsi_cmnd { ... SCp = { ptr = 0x0, <--- iscsi_task this_residual = 0, ... }, } To prevent this, we take a ref to the cmd under the back (completion) lock so if the completion side were to call iscsi_complete_task on the task while the timer/eh paths are not holding the back_lock it will not be freed from under us. Note that this requires the previous patch, "libiscsi: drop taskqueuelock" because bnx2i sleeps in its cleanup_task callout if the cmd is aborted. If the EH/timer and completion path are racing we don't know which path will do the last put. The previous patch moved the operations we needed to do under the forward lock to cleanup_queued_task. Once that has run we can drop the forward lock for the cmd and bnx2i no longer has to worry about if the EH, timer or completion path did the ast put and if the forward lock is held or not since it won't be. Reported-by: Wu Bo Signed-off-by: Mike Christie Reviewed-by: Lee Duncan --- drivers/scsi/bnx2i/bnx2i_iscsi.c | 2 -- drivers/scsi/libiscsi.c | 71 +++++++++++++++++++++++++--------------- 2 files changed, 45 insertions(+), 28 deletions(-) diff --git a/drivers/scsi/bnx2i/bnx2i_iscsi.c b/drivers/scsi/bnx2i/bnx2i_iscsi.c index fdd4467..1e6d8f6 100644 --- a/drivers/scsi/bnx2i/bnx2i_iscsi.c +++ b/drivers/scsi/bnx2i/bnx2i_iscsi.c @@ -1171,10 +1171,8 @@ static void bnx2i_cleanup_task(struct iscsi_task *task) bnx2i_send_cmd_cleanup_req(hba, task->dd_data); spin_unlock_bh(&conn->session->back_lock); - spin_unlock_bh(&conn->session->frwd_lock); wait_for_completion_timeout(&bnx2i_conn->cmd_cleanup_cmpl, msecs_to_jiffies(ISCSI_CMD_CLEANUP_TIMEOUT)); - spin_lock_bh(&conn->session->frwd_lock); spin_lock_bh(&conn->session->back_lock); } bnx2i_iscsi_unmap_sg_list(task->dd_data); diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 5582e4f..796465e 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -587,9 +587,8 @@ static bool cleanup_queued_task(struct iscsi_task *task) } /* - * session frwd_lock must be held and if not called for a task that is - * still pending or from the xmit thread, then xmit thread must - * be suspended. + * session frwd lock must be held and if not called for a task that is still + * pending or from the xmit thread, then xmit thread must be suspended */ static void fail_scsi_task(struct iscsi_task *task, int err) { @@ -597,16 +596,6 @@ static void fail_scsi_task(struct iscsi_task *task, int err) struct scsi_cmnd *sc; int state; - /* - * if a command completes and we get a successful tmf response - * we will hit this because the scsi eh abort code does not take - * a ref to the task. - */ - sc = task->sc; - if (!sc) - return; - - /* regular RX path uses back_lock */ spin_lock_bh(&conn->session->back_lock); if (cleanup_queued_task(task)) { spin_unlock_bh(&conn->session->back_lock); @@ -626,6 +615,7 @@ static void fail_scsi_task(struct iscsi_task *task, int err) else state = ISCSI_TASK_ABRT_TMF; + sc = task->sc; sc->result = err << 16; scsi_set_resid(sc, scsi_bufflen(sc)); iscsi_complete_task(task, state); @@ -1893,27 +1883,39 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn, } /* - * Fail commands. session lock held and recv side suspended and xmit - * thread flushed + * Fail commands. session frwd lock held and xmit thread flushed. */ static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error) { + struct iscsi_session *session = conn->session; struct iscsi_task *task; int i; - for (i = 0; i < conn->session->cmds_max; i++) { - task = conn->session->cmds[i]; + spin_lock_bh(&session->back_lock); + for (i = 0; i < session->cmds_max; i++) { + task = session->cmds[i]; if (!task->sc || task->state == ISCSI_TASK_FREE) continue; if (lun != -1 && lun != task->sc->device->lun) continue; - ISCSI_DBG_SESSION(conn->session, + __iscsi_get_task(task); + spin_unlock_bh(&session->back_lock); + + ISCSI_DBG_SESSION(session, "failing sc %p itt 0x%x state %d\n", task->sc, task->itt, task->state); fail_scsi_task(task, error); + + spin_unlock_bh(&session->frwd_lock); + iscsi_put_task(task); + spin_lock_bh(&session->frwd_lock); + + spin_lock_bh(&session->back_lock); } + + spin_unlock_bh(&session->back_lock); } /** @@ -1991,6 +1993,7 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc); spin_lock_bh(&session->frwd_lock); + spin_lock(&session->back_lock); task = (struct iscsi_task *)sc->SCp.ptr; if (!task) { /* @@ -1998,8 +2001,11 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) * so let timeout code complete it now. */ rc = BLK_EH_DONE; + spin_unlock(&session->back_lock); goto done; } + __iscsi_get_task(task); + spin_unlock(&session->back_lock); if (session->state != ISCSI_STATE_LOGGED_IN) { /* @@ -2058,6 +2064,7 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) goto done; } + spin_lock(&session->back_lock); for (i = 0; i < conn->session->cmds_max; i++) { running_task = conn->session->cmds[i]; if (!running_task->sc || running_task == task || @@ -2090,10 +2097,12 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) "last xfer %lu/%lu. Last check %lu.\n", task->last_xfer, running_task->last_xfer, task->last_timeout); + spin_unlock(&session->back_lock); rc = BLK_EH_RESET_TIMER; goto done; } } + spin_unlock(&session->back_lock); /* Assumes nop timeout is shorter than scsi cmd timeout */ if (task->have_checked_conn) @@ -2115,9 +2124,12 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc) rc = BLK_EH_RESET_TIMER; done: - if (task) - task->last_timeout = jiffies; spin_unlock_bh(&session->frwd_lock); + + if (task) { + task->last_timeout = jiffies; + iscsi_put_task(task); + } ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ? "timer reset" : "shutdown or nh"); return rc; @@ -2225,15 +2237,20 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) conn->eh_abort_cnt++; age = session->age; + spin_lock(&session->back_lock); task = (struct iscsi_task *)sc->SCp.ptr; - ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n", - sc, task->itt); - - /* task completed before time out */ - if (!task->sc) { + if (!task || !task->sc) { + /* task completed before time out */ ISCSI_DBG_EH(session, "sc completed while abort in progress\n"); - goto success; + + spin_unlock(&session->back_lock); + spin_unlock_bh(&session->frwd_lock); + mutex_unlock(&session->eh_mutex); + return SUCCESS; } + ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n", sc, task->itt); + __iscsi_get_task(task); + spin_unlock(&session->back_lock); if (task->state == ISCSI_TASK_PENDING) { fail_scsi_task(task, DID_ABORT); @@ -2295,6 +2312,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) success_unlocked: ISCSI_DBG_EH(session, "abort success [sc %p itt 0x%x]\n", sc, task->itt); + iscsi_put_task(task); mutex_unlock(&session->eh_mutex); return SUCCESS; @@ -2303,6 +2321,7 @@ int iscsi_eh_abort(struct scsi_cmnd *sc) failed_unlocked: ISCSI_DBG_EH(session, "abort failed [sc %p itt 0x%x]\n", sc, task ? task->itt : 0); + iscsi_put_task(task); mutex_unlock(&session->eh_mutex); return FAILED; }