6.1-stable review patch. If anyone has any objections, please let me know.
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From: Meir Elisha meir.elisha@volumez.com
[ Upstream commit a16f88964c647103dad7743a484b216d488a6352 ]
The order in which queue->cmd and rcv_state are updated is crucial. If these assignments are reordered by the compiler, the worker might not get queued in nvmet_tcp_queue_response(), hanging the IO. to enforce the the correct reordering, set rcv_state using smp_store_release().
Fixes: bdaf13279192 ("nvmet-tcp: fix a segmentation fault during io parsing error")
Signed-off-by: Meir Elisha meir.elisha@volumez.com Reviewed-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Keith Busch kbusch@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/target/tcp.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 81574500a57c7..125e22bd34e2a 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -520,10 +520,16 @@ static void nvmet_tcp_queue_response(struct nvmet_req *req) struct nvmet_tcp_cmd *cmd = container_of(req, struct nvmet_tcp_cmd, req); struct nvmet_tcp_queue *queue = cmd->queue; + enum nvmet_tcp_recv_state queue_state; + struct nvmet_tcp_cmd *queue_cmd; struct nvme_sgl_desc *sgl; u32 len;
- if (unlikely(cmd == queue->cmd)) { + /* Pairs with store_release in nvmet_prepare_receive_pdu() */ + queue_state = smp_load_acquire(&queue->rcv_state); + queue_cmd = READ_ONCE(queue->cmd); + + if (unlikely(cmd == queue_cmd)) { sgl = &cmd->req.cmd->common.dptr.sgl; len = le32_to_cpu(sgl->length);
@@ -532,7 +538,7 @@ static void nvmet_tcp_queue_response(struct nvmet_req *req) * Avoid using helpers, this might happen before * nvmet_req_init is completed. */ - if (queue->rcv_state == NVMET_TCP_RECV_PDU && + if (queue_state == NVMET_TCP_RECV_PDU && len && len <= cmd->req.port->inline_data_size && nvme_is_write(cmd->req.cmd)) return; @@ -784,8 +790,9 @@ static void nvmet_prepare_receive_pdu(struct nvmet_tcp_queue *queue) { queue->offset = 0; queue->left = sizeof(struct nvme_tcp_hdr); - queue->cmd = NULL; - queue->rcv_state = NVMET_TCP_RECV_PDU; + WRITE_ONCE(queue->cmd, NULL); + /* Ensure rcv_state is visible only after queue->cmd is set */ + smp_store_release(&queue->rcv_state, NVMET_TCP_RECV_PDU); }
static void nvmet_tcp_free_crypto(struct nvmet_tcp_queue *queue)