Commit 5293a888 authored Apr 08, 2026 by Chaitanya Kulkarni Committed by Keith Busch Apr 09, 2026

nvmet-tcp: fix race between ICReq handling and queue teardown



nvmet_tcp_handle_icreq() updates queue->state after sending an
Initialization Connection Response (ICResp), but it does so without
serializing against target-side queue teardown.

If an NVMe/TCP host sends an Initialization Connection Request
(ICReq) and immediately closes the connection, target-side teardown
may start in softirq context before io_work drains the already
buffered ICReq. In that case, nvmet_tcp_schedule_release_queue()
sets queue->state to NVMET_TCP_Q_DISCONNECTING and drops the queue
reference under state_lock.

If io_work later processes that ICReq, nvmet_tcp_handle_icreq() can
still overwrite the state back to NVMET_TCP_Q_LIVE. That defeats the
DISCONNECTING-state guard in nvmet_tcp_schedule_release_queue() and
allows a later socket state change to re-enter teardown and issue a
second kref_put() on an already released queue.

The ICResp send failure path has the same problem. If teardown has
already moved the queue to DISCONNECTING, a send error can still
overwrite the state with NVMET_TCP_Q_FAILED, again reopening the
window for a second teardown path to drop the queue reference.

Fix this by serializing both post-send state transitions with
state_lock and bailing out if teardown has already started.

Use -ESHUTDOWN as an internal sentinel for that bail-out path rather
than propagating it as a transport error like -ECONNRESET. Keep
nvmet_tcp_socket_error() setting rcv_state to NVMET_TCP_RECV_ERR before
honoring that sentinel so receive-side parsing stays quiesced until the
existing release path completes.

Fixes: c46a6465bac2 ("nvmet-tcp: add NVMe over TCP target driver")
Cc: stable@vger.kernel.org
Reported-by: Shivam Kumar <skumar47@syr.edu>
Tested-by: Shivam Kumar <kumar.shivam43666@gmail.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

parent bad44c9c

drivers/nvme/target/tcp.c

+26 −0

Original line number	Diff line number	Diff line
		@@ -394,6 +394,19 @@ static int nvmet_tcp_build_pdu_iovec(struct nvmet_tcp_cmd *cmd)

		static void nvmet_tcp_socket_error(struct nvmet_tcp_queue *queue, int status)
		{
		/*
		* Keep rcv_state at RECV_ERR even for the internal -ESHUTDOWN path.
		* nvmet_tcp_handle_icreq() can return -ESHUTDOWN after the ICReq has
		* already been consumed and queue teardown has started.
		*
		* If nvmet_tcp_data_ready() or nvmet_tcp_write_space() queues
		* nvmet_tcp_io_work() again before nvmet_tcp_release_queue_work()
		* cancels it, the queue must not keep that old receive state.
		* Otherwise the next nvmet_tcp_io_work() run can reach
		* nvmet_tcp_done_recv_pdu() and try to handle the same ICReq again.
		*
		* That is why queue->rcv_state needs to be updated before we return.
		*/
		queue->rcv_state = NVMET_TCP_RECV_ERR;
		if (status == -EPIPE \|\| status == -ECONNRESET \|\| !queue->nvme_sq.ctrl)
		kernel_sock_shutdown(queue->sock, SHUT_RDWR);
		@@ -908,11 +921,24 @@ static int nvmet_tcp_handle_icreq(struct nvmet_tcp_queue *queue)
		iov.iov_len = sizeof(*icresp);
		ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
		if (ret < 0) {
		spin_lock_bh(&queue->state_lock);
		if (queue->state == NVMET_TCP_Q_DISCONNECTING) {
		spin_unlock_bh(&queue->state_lock);
		return -ESHUTDOWN;
		}
		queue->state = NVMET_TCP_Q_FAILED;
		spin_unlock_bh(&queue->state_lock);
		return ret; /* queue removal will cleanup */
		}

		spin_lock_bh(&queue->state_lock);
		if (queue->state == NVMET_TCP_Q_DISCONNECTING) {
		spin_unlock_bh(&queue->state_lock);
		/* Tell nvmet_tcp_socket_error() teardown is in progress. */
		return -ESHUTDOWN;
		}
		queue->state = NVMET_TCP_Q_LIVE;
		spin_unlock_bh(&queue->state_lock);
		nvmet_prepare_receive_pdu(queue);
		return 0;
		}