[PATCH] nvmet-tcp: fix a segmentation fault during io parsing error

[elad.grupi at dell.com]

From: Elad Grupi <elad.grupi at dell.com>

In case there is an io that contains inline data and it goes to
parsing error flow, command response will free command and iov
before clearing the data on the socket buffer.
This will delay the command response until receive flow is completed.

Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver")
Signed-off-by: Elad Grupi <elad.grupi at dell.com>
---
 drivers/nvme/target/tcp.c | 42 +++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 70cc507d1565..f10fa2b5aaeb 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -154,6 +154,7 @@ static struct workqueue_struct *nvmet_tcp_wq;
 static const struct nvmet_fabrics_ops nvmet_tcp_ops;
 static void nvmet_tcp_free_cmd(struct nvmet_tcp_cmd *c);
 static void nvmet_tcp_finish_cmd(struct nvmet_tcp_cmd *cmd);
+static void nvmet_tcp_queue_response(struct nvmet_req *req);
 
 static inline u16 nvmet_tcp_cmd_tag(struct nvmet_tcp_queue *queue,
 		struct nvmet_tcp_cmd *cmd)
@@ -526,6 +527,12 @@ static void nvmet_tcp_queue_response(struct nvmet_req *req)
 		container_of(req, struct nvmet_tcp_cmd, req);
 	struct nvmet_tcp_queue	*queue = cmd->queue;
 
+	if (unlikely((cmd->flags & NVMET_TCP_F_INIT_FAILED) &&
+			nvmet_tcp_has_inline_data(cmd))) {
+		/* fail the cmd when we finish processing the inline data */
+		return;
+	}
+
 	llist_add(&cmd->lentry, &queue->resp_list);
 	queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &cmd->queue->io_work);
 }
@@ -702,6 +709,17 @@ static int nvmet_tcp_try_send_one(struct nvmet_tcp_queue *queue,
 			return 0;
 	}
 
+	if (unlikely((cmd->flags & NVMET_TCP_F_INIT_FAILED) &&
+			nvmet_tcp_has_data_in(cmd) &&
+			nvmet_tcp_has_inline_data(cmd))) {
+		/*
+		 * wait for inline data before processing the response
+		 * so the iov will not be freed
+		 */
+		queue->snd_cmd = NULL;
+		goto done_send;
+	}
+
 	if (cmd->state == NVMET_TCP_SEND_DATA_PDU) {
 		ret = nvmet_try_send_data_pdu(cmd);
 		if (ret <= 0)
@@ -1103,9 +1121,14 @@ static int nvmet_tcp_try_recv_data(struct nvmet_tcp_queue *queue)
 		return 0;
 	}
 
-	if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED) &&
-	    cmd->rbytes_done == cmd->req.transfer_len) {
-		cmd->req.execute(&cmd->req);
+	if (cmd->rbytes_done == cmd->req.transfer_len) {
+		if (unlikely(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+			nvmet_tcp_queue_response(&cmd->req);
+		else {
+			if (unlikely(cmd == &queue->connect))
+				nvmet_tcp_executing_connect_cmd(queue);
+			cmd->req.execute(&cmd->req);
+		}
 	}
 
 	nvmet_prepare_receive_pdu(queue);
@@ -1143,9 +1166,16 @@ static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
 		goto out;
 	}
 
-	if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED) &&
-	    cmd->rbytes_done == cmd->req.transfer_len)
-		cmd->req.execute(&cmd->req);
+	if (cmd->rbytes_done == cmd->req.transfer_len) {
+		if (unlikely(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+			nvmet_tcp_queue_response(&cmd->req);
+		else {
+			if (unlikely(cmd == &queue->connect))
+				nvmet_tcp_executing_connect_cmd(queue);
+			cmd->req.execute(&cmd->req);
+		}
+	}
+
 	ret = 0;
 out:
 	nvmet_prepare_receive_pdu(queue);
-- 
2.18.2