diff mbox series

[v4,10/17] scsi: qedi: fix use after free during abort cleanup

Message ID 20210424220603.123703-11-michael.christie@oracle.com
State New
Headers show
Series libiscsi and qedi TMF fixes | expand

Commit Message

Mike Christie April 24, 2021, 10:05 p.m. UTC 
This fixes two bugs:

1. The scsi cmd task could be completed and the abort could timeout while
we are running qedi_tmf_work so we need to get a ref to the task.

2. If qedi_tmf_work's qedi_wait_for_cleanup_request call times out we will
also force the clean up of the qedi_work_map but
qedi_process_cmd_cleanup_resp could still be accessing the qedi_cmd for the
abort TMF. We can then race where qedi_process_cmd_cleanup_resp is still
accessing the mtask's qedi_cmd but libiscsi has escalated to session level
cleanup and is cleaning up the mtask while we are still accessing it.

To fix this issue we extend where we hold the tmf_work_lock and back_lock
so the qedi_process_cmd_cleanup_resp access is serialized with the cleanup
done in qedi_tmf_work and any completion handling for the iscsi_task.

Reviewed-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/qedi/qedi_fw.c    | 110 ++++++++++++++++++---------------
 drivers/scsi/qedi/qedi_iscsi.h |   1 +
 2 files changed, 61 insertions(+), 50 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/qedi/qedi_fw.c b/drivers/scsi/qedi/qedi_fw.c
index c12bb2dd5ff9..b53940af4230 100644
--- a/drivers/scsi/qedi/qedi_fw.c
+++ b/drivers/scsi/qedi/qedi_fw.c
@@ -729,7 +729,6 @@  static void qedi_process_nopin_local_cmpl(struct qedi_ctx *qedi,
 
 static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
 					  struct iscsi_cqe_solicited *cqe,
-					  struct iscsi_task *task,
 					  struct iscsi_conn *conn)
 {
 	struct qedi_work_map *work, *work_tmp;
@@ -741,7 +740,7 @@  static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
 	u32 iscsi_cid;
 	struct qedi_conn *qedi_conn;
 	struct qedi_cmd *dbg_cmd;
-	struct iscsi_task *mtask;
+	struct iscsi_task *mtask, *task;
 	struct iscsi_tm *tmf_hdr = NULL;
 
 	iscsi_cid = cqe->conn_id;
@@ -767,6 +766,7 @@  static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
 			}
 			found = 1;
 			mtask = qedi_cmd->task;
+			task = work->ctask;
 			tmf_hdr = (struct iscsi_tm *)mtask->hdr;
 
 			list_del_init(&work->list);
@@ -774,52 +774,47 @@  static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
 			qedi_cmd->list_tmf_work = NULL;
 		}
 	}
-	spin_unlock_bh(&qedi_conn->tmf_work_lock);
-
-	if (found) {
-		QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM,
-			  "TMF work, cqe->tid=0x%x, tmf flags=0x%x, cid=0x%x\n",
-			  proto_itt, tmf_hdr->flags, qedi_conn->iscsi_conn_id);
-
-		if ((tmf_hdr->flags & ISCSI_FLAG_TM_FUNC_MASK) ==
-		    ISCSI_TM_FUNC_ABORT_TASK) {
-			spin_lock_bh(&conn->session->back_lock);
 
-			protoitt = build_itt(get_itt(tmf_hdr->rtt),
-					     conn->session->age);
-			task = iscsi_itt_to_task(conn, protoitt);
-
-			spin_unlock_bh(&conn->session->back_lock);
+	if (!found) {
+		spin_unlock_bh(&qedi_conn->tmf_work_lock);
+		goto check_cleanup_reqs;
+	}
 
-			if (!task) {
-				QEDI_NOTICE(&qedi->dbg_ctx,
-					    "IO task completed, tmf rtt=0x%x, cid=0x%x\n",
-					    get_itt(tmf_hdr->rtt),
-					    qedi_conn->iscsi_conn_id);
-				return;
-			}
+	QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM,
+		  "TMF work, cqe->tid=0x%x, tmf flags=0x%x, cid=0x%x\n",
+		  proto_itt, tmf_hdr->flags, qedi_conn->iscsi_conn_id);
+
+	spin_lock_bh(&conn->session->back_lock);
+	if (iscsi_task_is_completed(task)) {
+		QEDI_NOTICE(&qedi->dbg_ctx,
+			    "IO task completed, tmf rtt=0x%x, cid=0x%x\n",
+			   get_itt(tmf_hdr->rtt), qedi_conn->iscsi_conn_id);
+		goto unlock;
+	}
 
-			dbg_cmd = task->dd_data;
+	dbg_cmd = task->dd_data;
 
-			QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM,
-				  "Abort tmf rtt=0x%x, i/o itt=0x%x, i/o tid=0x%x, cid=0x%x\n",
-				  get_itt(tmf_hdr->rtt), get_itt(task->itt),
-				  dbg_cmd->task_id, qedi_conn->iscsi_conn_id);
+	QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM,
+		  "Abort tmf rtt=0x%x, i/o itt=0x%x, i/o tid=0x%x, cid=0x%x\n",
+		  get_itt(tmf_hdr->rtt), get_itt(task->itt), dbg_cmd->task_id,
+		  qedi_conn->iscsi_conn_id);
 
-			if (qedi_cmd->state == CLEANUP_WAIT_FAILED)
-				qedi_cmd->state = CLEANUP_RECV;
+	spin_lock(&qedi_conn->list_lock);
+	if (likely(dbg_cmd->io_cmd_in_list)) {
+		dbg_cmd->io_cmd_in_list = false;
+		list_del_init(&dbg_cmd->io_cmd);
+		qedi_conn->active_cmd_count--;
+	}
+	spin_unlock(&qedi_conn->list_lock);
+	qedi_cmd->state = CLEANUP_RECV;
+unlock:
+	spin_unlock_bh(&conn->session->back_lock);
+	spin_unlock_bh(&qedi_conn->tmf_work_lock);
+	wake_up_interruptible(&qedi_conn->wait_queue);
+	return;
 
-			spin_lock(&qedi_conn->list_lock);
-			if (likely(dbg_cmd->io_cmd_in_list)) {
-				dbg_cmd->io_cmd_in_list = false;
-				list_del_init(&dbg_cmd->io_cmd);
-				qedi_conn->active_cmd_count--;
-			}
-			spin_unlock(&qedi_conn->list_lock);
-			qedi_cmd->state = CLEANUP_RECV;
-			wake_up_interruptible(&qedi_conn->wait_queue);
-		}
-	} else if (qedi_conn->cmd_cleanup_req > 0) {
+check_cleanup_reqs:
+	if (qedi_conn->cmd_cleanup_req > 0) {
 		spin_lock_bh(&conn->session->back_lock);
 		qedi_get_proto_itt(qedi, cqe->itid, &ptmp_itt);
 		protoitt = build_itt(ptmp_itt, conn->session->age);
@@ -842,6 +837,7 @@  static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
 		QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_TID,
 			  "Freeing tid=0x%x for cid=0x%x\n",
 			  cqe->itid, qedi_conn->iscsi_conn_id);
+		qedi_clear_task_idx(qedi_conn->qedi, cqe->itid);
 
 	} else {
 		qedi_get_proto_itt(qedi, cqe->itid, &ptmp_itt);
@@ -944,8 +940,7 @@  void qedi_fp_process_cqes(struct qedi_work *work)
 		goto exit_fp_process;
 	case ISCSI_CQE_TYPE_TASK_CLEANUP:
 		QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM, "CleanUp CqE\n");
-		qedi_process_cmd_cleanup_resp(qedi, &cqe->cqe_solicited, task,
-					      conn);
+		qedi_process_cmd_cleanup_resp(qedi, &cqe->cqe_solicited, conn);
 		goto exit_fp_process;
 	default:
 		QEDI_ERR(&qedi->dbg_ctx, "Error cqe.\n");
@@ -1372,12 +1367,22 @@  static void qedi_tmf_work(struct work_struct *work)
 	tmf_hdr = (struct iscsi_tm *)mtask->hdr;
 	set_bit(QEDI_CONN_FW_CLEANUP, &qedi_conn->flags);
 
-	ctask = iscsi_itt_to_task(conn, tmf_hdr->rtt);
-	if (!ctask || !ctask->sc) {
+	spin_lock_bh(&conn->session->back_lock);
+	ctask = iscsi_itt_to_ctask(conn, tmf_hdr->rtt);
+	if (!ctask || iscsi_task_is_completed(ctask)) {
+		spin_unlock_bh(&conn->session->back_lock);
 		QEDI_ERR(&qedi->dbg_ctx, "Task already completed\n");
-		goto abort_ret;
+		goto clear_cleanup;
 	}
 
+	/*
+	 * libiscsi gets a ref before sending the abort, but if libiscsi times
+	 * it out then it could release it and the cmd could complete from
+	 * under us.
+	 */
+	__iscsi_get_task(ctask);
+	spin_unlock_bh(&conn->session->back_lock);
+
 	cmd = (struct qedi_cmd *)ctask->dd_data;
 	QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_INFO,
 		  "Abort tmf rtt=0x%x, cmd itt=0x%x, cmd tid=0x%x, cid=0x%x\n",
@@ -1387,19 +1392,20 @@  static void qedi_tmf_work(struct work_struct *work)
 	if (qedi_do_not_recover) {
 		QEDI_ERR(&qedi->dbg_ctx, "DONT SEND CLEANUP/ABORT %d\n",
 			 qedi_do_not_recover);
-		goto abort_ret;
+		goto put_task;
 	}
 
 	list_work = kzalloc(sizeof(*list_work), GFP_ATOMIC);
 	if (!list_work) {
 		QEDI_ERR(&qedi->dbg_ctx, "Memory allocation failed\n");
-		goto abort_ret;
+		goto put_task;
 	}
 
 	qedi_cmd->type = TYPEIO;
 	list_work->qedi_cmd = qedi_cmd;
 	list_work->rtid = cmd->task_id;
 	list_work->state = QEDI_WORK_SCHEDULED;
+	list_work->ctask = ctask;
 	qedi_cmd->list_tmf_work = list_work;
 
 	QEDI_INFO(&qedi->dbg_ctx, QEDI_LOG_SCSI_TM,
@@ -1432,7 +1438,9 @@  static void qedi_tmf_work(struct work_struct *work)
 	qedi_cmd->task_id = tid;
 	qedi_send_iscsi_tmf(qedi_conn, qedi_cmd->task);
 
-abort_ret:
+put_task:
+	iscsi_put_task(ctask);
+clear_cleanup:
 	clear_bit(QEDI_CONN_FW_CLEANUP, &qedi_conn->flags);
 	return;
 
@@ -1453,6 +1461,8 @@  static void qedi_tmf_work(struct work_struct *work)
 	}
 	spin_unlock(&qedi_conn->list_lock);
 
+	iscsi_put_task(ctask);
+
 	clear_bit(QEDI_CONN_FW_CLEANUP, &qedi_conn->flags);
 }
 
diff --git a/drivers/scsi/qedi/qedi_iscsi.h b/drivers/scsi/qedi/qedi_iscsi.h
index 39dc27c85e3c..68ef519f5480 100644
--- a/drivers/scsi/qedi/qedi_iscsi.h
+++ b/drivers/scsi/qedi/qedi_iscsi.h
@@ -212,6 +212,7 @@  struct qedi_cmd {
 struct qedi_work_map {
 	struct list_head list;
 	struct qedi_cmd *qedi_cmd;
+	struct iscsi_task *ctask;
 	int rtid;
 
 	int state;