From: Sagi Grimberg <s...@grimberg.me>

commit fd0823f405090f9f410fc3e3ff7efb52e7b486fa upstream.

When the controller sends us a 0-length r2t PDU we should not attempt to
try to set up a h2cdata PDU but rather conclude that this is a buggy
controller (forward progress is not possible) and simply fail it
immediately.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Reported-by: Belanger, Martin <martin.belan...@dell.com>
Signed-off-by: Sagi Grimberg <s...@grimberg.me>
Signed-off-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/nvme/host/tcp.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -568,6 +568,13 @@ static int nvme_tcp_setup_h2c_data_pdu(s
        req->pdu_len = le32_to_cpu(pdu->r2t_length);
        req->pdu_sent = 0;
 
+       if (unlikely(!req->pdu_len)) {
+               dev_err(queue->ctrl->ctrl.device,
+                       "req %d r2t len is %u, probably a bug...\n",
+                       rq->tag, req->pdu_len);
+               return -EPROTO;
+       }
+
        if (unlikely(req->data_sent + req->pdu_len > req->data_len)) {
                dev_err(queue->ctrl->ctrl.device,
                        "req %d r2t len %u exceeded data len %u (%zu sent)\n",


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