From ce7723e9cdae4eb3030da082876580f4b2dc0861 Mon Sep 17 00:00:00 2001 From: Varun Prakash Date: Tue, 26 Oct 2021 19:01:55 +0530 Subject: nvme-tcp: fix possible req->offset corruption 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 Reviewed-by: Keith Busch Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig --- drivers/nvme/host/tcp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 0626d14e6d4c..1a209f0d7181 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -1050,6 +1050,7 @@ static int nvme_tcp_try_send_data_pdu(struct nvme_tcp_request *req) 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 = { @@ -1066,7 +1067,7 @@ static int nvme_tcp_try_send_ddgst(struct nvme_tcp_request *req) 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; } -- cgit v1.2.3-70-g09d2