From: James Smart <jsmart2021@gmail.com>
Date: Thu, 15 Jun 2017 23:41:41 -0700
Subject: nvmet_fc: fix crashes on bad opcodes
Patch-mainline: v4.13-rc1
Git-commit: 188f7e8a3789cb2e37b68903e0a40f406091fa97
References: FATE#323952, FATE#322506

if a nvme command is issued with an opcode that is not supported by
the target (example: opcode 21 - detach namespace), the target
crashes due to a null pointer.

nvmet_req_init() detects the bad opcode and immediately calls the nvme
command done routine with an error status, allowing the transport to
send the response. However, the FC transport was aborting the command
on error, so the abort freed the lldd point, but the rsp transmit path
referenced it psot the free.

Fix by removing the abort call on nvmet_req_init() failure.
The completion response will be sent with an error status code.

As the completion path will terminate the io, ensure the data_sg
lists show an unused state so that teardown paths are successful.

Signed-off-by: Paul Ely <Paul.Ely@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/nvme/target/fc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 2006fae61980..7692a96c9065 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -2096,20 +2096,22 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	/* clear any response payload */
 	memset(&fod->rspiubuf, 0, sizeof(fod->rspiubuf));
 
+	fod->data_sg = NULL;
+	fod->data_sg_cnt = 0;
+
 	ret = nvmet_req_init(&fod->req,
 				&fod->queue->nvme_cq,
 				&fod->queue->nvme_sq,
 				&nvmet_fc_tgt_fcp_ops);
-	if (!ret) {	/* bad SQE content or invalid ctrl state */
-		nvmet_fc_abort_op(tgtport, fod);
+	if (!ret) {
+		/* bad SQE content or invalid ctrl state */
+		/* nvmet layer has already called op done to send rsp. */
 		return;
 	}
 
 	/* keep a running counter of tail position */
 	atomic_inc(&fod->queue->sqtail);
 
-	fod->data_sg = NULL;
-	fod->data_sg_cnt = 0;
 	if (fod->total_length) {
 		ret = nvmet_fc_alloc_tgt_pgs(fod);
 		if (ret) {
-- 
2.12.3