From: Varun Prakash varun@chelsio.com
commit ce7723e9cdae4eb3030da082876580f4b2dc0861 upstream.
With commit db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq context") r2t and response PDU can get processed while send function is executing.
Current data digest send code uses req->offset after kernel_sendmsg(), this creates a race condition where req->offset gets reset before it is used in send function.
This can happen in two cases - 1. Target sends r2t PDU which resets req->offset. 2. Target send response PDU which completes the req and then req is used for a new command, nvme_tcp_setup_cmd_pdu() resets req->offset.
Fix this by storing req->offset in a local variable and using this local variable after kernel_sendmsg().
Fixes: db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq context") Signed-off-by: Varun Prakash varun@chelsio.com Reviewed-by: Keith Busch kbusch@kernel.org Reviewed-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nvme/host/tcp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -1037,6 +1037,7 @@ static int nvme_tcp_try_send_data_pdu(st static int nvme_tcp_try_send_ddgst(struct nvme_tcp_request *req) { struct nvme_tcp_queue *queue = req->queue; + size_t offset = req->offset; int ret; struct msghdr msg = { .msg_flags = MSG_DONTWAIT }; struct kvec iov = { @@ -1053,7 +1054,7 @@ static int nvme_tcp_try_send_ddgst(struc if (unlikely(ret <= 0)) return ret;
- if (req->offset + ret == NVME_TCP_DIGEST_LENGTH) { + if (offset + ret == NVME_TCP_DIGEST_LENGTH) { nvme_tcp_done_send_req(queue); return 1; }