[PATCH 17/33] scsi: qla2xxx: Quiesce response IRQ before freeing request queue

qla2xxx_delete_qpair() deletes the request queue before the response
queue. qla25xx_delete_req_que() frees the request queue memory
(kfree(req) in qla25xx_free_req_que()), but the response-queue MSI-X is
only released later, in qla25xx_free_rsp_que(). In that window the
response interrupt can still fire, qla2xxx_msix_rsp_q() queues
qpair->q_work, and qla_do_work() -> qla24xx_process_response_queue()
dereferences the now-freed rsp->req (LOGINOUT/CT/ELS entries and the
status path), a use-after-free.

The cancel_work_sync() added for the qpair teardown lives in the
response free path, which runs after the request queue is already freed,
so it does not protect rsp->req.

Release the response-queue interrupt and flush qpair->q_work before
deleting the request queue, so no late completion can reach the freed
request queue. Clearing have_irq makes the subsequent
qla25xx_free_rsp_que() skip its free_irq(), and the firmware
queue-delete order (request then response) is preserved; the
request-delete mailbox completes on the default vector and is unaffected
by dropping the qpair response interrupt early.

Fixes: d74595278f4a ("scsi: qla2xxx: Add multiple queue pair functionality.")
Cc: [email protected]
Reported-by: Sashiko <[email protected]>
Signed-off-by: Nilesh Javali <[email protected]>
---
 drivers/scsi/qla2xxx/qla_init.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index fed6dbc3b6ae..e6b499245794 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -10695,11 +10695,28 @@ int qla2xxx_delete_qpair(struct scsi_qla_host *vha, struct qla_qpair *qpair)
 {
 	int ret = QLA_FUNCTION_FAILED;
 	struct qla_hw_data *ha = qpair->hw;
+	struct rsp_que *rsp = qpair->rsp;
 
 	qpair->delete_in_progress = 1;
 
 	qla_free_buf_pool(qpair);
 
+	/*
+	 * The response-queue interrupt schedules qla_do_work(), which
+	 * dereferences qpair->rsp->req.  Release the interrupt and flush
+	 * any pending work before the request queue is freed below so a
+	 * late completion cannot touch the freed request queue.  The
+	 * firmware queue-delete order (request then response) is kept.
+	 */
+	if (rsp && rsp->msix && rsp->msix->have_irq) {
+		free_irq(rsp->msix->vector, rsp->msix->handle);
+		rsp->msix->have_irq = 0;
+		rsp->msix->in_use = 0;
+		rsp->msix->handle = NULL;
+	}
+	if (rsp && ha->wq)
+		cancel_work_sync(&qpair->q_work);
+
 	ret = qla25xx_delete_req_que(vha, qpair->req);
 	if (ret != QLA_SUCCESS)
 		goto fail;
-- 
2.47.3