From: Sagi Grimberg <sagi@grimberg.me>
Date: Wed, 24 Apr 2019 11:53:18 -0700
Subject: [PATCH] nvme-rdma: fix a NULL deref when an admin connect times out
Git-commit: 1007709d7d06fab09bf2d007657575958676282b
Patch-Mainline: v5.2-rc1
References: bsc#1149446

If we timeout the admin startup sequence we might not yet have
an I/O tagset allocated which causes the teardown sequence to crash.
Make nvme_tcp_teardown_io_queues safe by not iterating inflight tags
if the tagset wasn't allocated.

Fixes: 4c174e636674 ("nvme-rdma: fix timeout handler")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/nvme/host/rdma.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 11a5ecae78c8..e1824c2e0a1c 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -914,8 +914,9 @@ static void nvme_rdma_teardown_admin_queue(struct nvme_rdma_ctrl *ctrl,
 {
 	blk_mq_quiesce_queue(ctrl->ctrl.admin_q);
 	nvme_rdma_stop_queue(&ctrl->queues[0]);
-	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set, nvme_cancel_request,
-			&ctrl->ctrl);
+	if (ctrl->ctrl.admin_tagset)
+		blk_mq_tagset_busy_iter(ctrl->ctrl.admin_tagset,
+			nvme_cancel_request, &ctrl->ctrl);
 	blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
 	nvme_rdma_destroy_admin_queue(ctrl, remove);
 }
@@ -926,8 +927,9 @@ static void nvme_rdma_teardown_io_queues(struct nvme_rdma_ctrl *ctrl,
 	if (ctrl->ctrl.queue_count > 1) {
 		nvme_stop_queues(&ctrl->ctrl);
 		nvme_rdma_stop_io_queues(ctrl);
-		blk_mq_tagset_busy_iter(&ctrl->tag_set, nvme_cancel_request,
-				&ctrl->ctrl);
+		if (ctrl->ctrl.tagset)
+			blk_mq_tagset_busy_iter(ctrl->ctrl.tagset,
+				nvme_cancel_request, &ctrl->ctrl);
 		if (remove)
 			nvme_start_queues(&ctrl->ctrl);
 		nvme_rdma_destroy_io_queues(ctrl, remove);
-- 
2.16.4