[PATCH 5.10 061/243] scsi: qedi: Fix race during abort timeouts

Greg Kroah-Hartman
2021-07-19T17:07:39Z

From: Mike Christie <michael.christie@oracle.com>

[ Upstream commit 2ce002366a3fcc3f9616d4583194f65dde0ad253 ]

If the SCSI cmd completes after qedi_tmf_work calls iscsi_itt_to_task then
the qedi qedi_cmd->task_id could be freed and used for another cmd. If we
then call qedi_iscsi_cleanup_task with that task_id we will be cleaning up
the wrong cmd.

Wait to release the task_id until the last put has been done on the
iscsi_task. Because libiscsi grabs a ref to the task when sending the
abort, we know that for the non-abort timeout case that the task_id we are
referencing is for the cmd that was supposed to be aborted.

A latter commit will fix the case where the abort times out while we are
running qedi_tmf_work.

Link: https://lore.kernel.org/r/20210525181821.7617-21-michael.christie@oracle.com
Reviewed-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qedi/qedi_fw.c | 15 ---------------
drivers/scsi/qedi/qedi_iscsi.c | 20 +++++++++++++++++---
2 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/qedi/qedi_fw.c b/drivers/scsi/qedi/qedi_fw.c
index cf57b4e49700..c12bb2dd5ff9 100644
--- a/drivers/scsi/qedi/qedi_fw.c
+++ b/drivers/scsi/qedi/qedi_fw.c
@@ -73,7 +73,6 @@ static void qedi_process_logout_resp(struct qedi_ctx *qedi,
spin_unlock(&qedi_conn->list_lock);

cmd->state = RESPONSE_RECEIVED;
- qedi_clear_task_idx(qedi, cmd->task_id);
__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr, NULL, 0);

spin_unlock(&session->back_lock);
@@ -138,7 +137,6 @@ static void qedi_process_text_resp(struct qedi_ctx *qedi,
spin_unlock(&qedi_conn->list_lock);

cmd->state = RESPONSE_RECEIVED;
- qedi_clear_task_idx(qedi, cmd->task_id);

__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr_ptr,
qedi_conn->gen_pdu.resp_buf,
@@ -164,13 +162,11 @@ static void qedi_tmf_resp_work(struct work_struct *work)
iscsi_block_session(session->cls_session);
rval = qedi_cleanup_all_io(qedi, qedi_conn, qedi_cmd->task, true);
if (rval) {
- qedi_clear_task_idx(qedi, qedi_cmd->task_id);
iscsi_unblock_session(session->cls_session);
goto exit_tmf_resp;
}

iscsi_unblock_session(session->cls_session);
- qedi_clear_task_idx(qedi, qedi_cmd->task_id);

spin_lock(&session->back_lock);
__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr_ptr, NULL, 0);
@@ -245,8 +241,6 @@ static void qedi_process_tmf_resp(struct qedi_ctx *qedi,
goto unblock_sess;
}

- qedi_clear_task_idx(qedi, qedi_cmd->task_id);
-
__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr_ptr, NULL, 0);
kfree(resp_hdr_ptr);

@@ -314,7 +308,6 @@ static void qedi_process_login_resp(struct qedi_ctx *qedi,
"Freeing tid=0x%x for cid=0x%x\n",
cmd->task_id, qedi_conn->iscsi_conn_id);
cmd->state = RESPONSE_RECEIVED;
- qedi_clear_task_idx(qedi, cmd->task_id);
}

static void qedi_get_rq_bdq_buf(struct qedi_ctx *qedi,
@@ -468,7 +461,6 @@ static int qedi_process_nopin_mesg(struct qedi_ctx *qedi,
}

spin_unlock(&qedi_conn->list_lock);
- qedi_clear_task_idx(qedi, cmd->task_id);
}

done:
@@ -673,7 +665,6 @@ static void qedi_scsi_completion(struct qedi_ctx *qedi,
if (qedi_io_tracing)
qedi_trace_io(qedi, task, cmd->task_id, QEDI_IO_TRACE_RSP);

- qedi_clear_task_idx(qedi, cmd->task_id);
__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr,
conn->data, datalen);
error:
@@ -730,7 +721,6 @@ static void qedi_process_nopin_local_cmpl(struct qedi_ctx *qedi,
cqe->itid, cmd->task_id);

cmd->state = RESPONSE_RECEIVED;
- qedi_clear_task_idx(qedi, cmd->task_id);

spin_lock_bh(&session->back_lock);
__iscsi_put_task(task);
@@ -748,7 +738,6 @@ static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
itt_t protoitt = 0;
int found = 0;
struct qedi_cmd *qedi_cmd = NULL;
- u32 rtid = 0;
u32 iscsi_cid;
struct qedi_conn *qedi_conn;
struct qedi_cmd *dbg_cmd;
@@ -779,7 +768,6 @@ static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
found = 1;
mtask = qedi_cmd->task;
tmf_hdr = (struct iscsi_tm *)mtask->hdr;
- rtid = work->rtid;

list_del_init(&work->list);
kfree(work);
@@ -821,8 +809,6 @@ static void qedi_process_cmd_cleanup_resp(struct qedi_ctx *qedi,
if (qedi_cmd->state == CLEANUP_WAIT_FAILED)
qedi_cmd->state = CLEANUP_RECV;

- qedi_clear_task_idx(qedi_conn->qedi, rtid);
-
spin_lock(&qedi_conn->list_lock);
if (likely(dbg_cmd->io_cmd_in_list)) {
dbg_cmd->io_cmd_in_list = false;
@@ -856,7 +842,6 @@ 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);
diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
index 08c05403cd72..604c4f408bc1 100644
--- a/drivers/scsi/qedi/qedi_iscsi.c
+++ b/drivers/scsi/qedi/qedi_iscsi.c
@@ -772,7 +772,6 @@ static int qedi_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
}

cmd->conn = conn->dd_data;
- cmd->scsi_cmd = NULL;
return qedi_iscsi_send_generic_request(task);
}

@@ -783,6 +782,10 @@ static int qedi_task_xmit(struct iscsi_task *task)
struct qedi_cmd *cmd = task->dd_data;
struct scsi_cmnd *sc = task->sc;

+ /* Clear now so in cleanup_task we know it didn't make it */
+ cmd->scsi_cmd = NULL;
+ cmd->task_id = U16_MAX;
+
if (test_bit(QEDI_IN_SHUTDOWN, &qedi_conn->qedi->flags))
return -ENODEV;

@@ -1383,13 +1386,24 @@ static umode_t qedi_attr_is_visible(int param_type, int param)

static void qedi_cleanup_task(struct iscsi_task *task)
{
- if (!task->sc || task->state == ISCSI_TASK_PENDING) {
+ struct qedi_cmd *cmd;
+
+ if (task->state == ISCSI_TASK_PENDING) {
QEDI_INFO(NULL, QEDI_LOG_IO, "Returning ref_cnt=%d\n",
refcount_read(&task->refcount));
return;
}

- qedi_iscsi_unmap_sg_list(task->dd_data);
+ if (task->sc)
+ qedi_iscsi_unmap_sg_list(task->dd_data);
+
+ cmd = task->dd_data;
+ if (cmd->task_id != U16_MAX)
+ qedi_clear_task_idx(iscsi_host_priv(task->conn->session->host),
+ cmd->task_id);
+
+ cmd->task_id = U16_MAX;
+ cmd->scsi_cmd = NULL;
}

struct iscsi_transport qedi_iscsi_transport = {
--
2.30.2