| From 397229be57920584aa097b86647f3783f670f8ed Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 5 Feb 2021 11:47:25 -0800 |
| Subject: nvmet-tcp: fix potential race of tcp socket closing accept_work |
| |
| From: Sagi Grimberg <sagi@grimberg.me> |
| |
| [ Upstream commit 0fbcfb089a3f2f2a731d01f0aec8f7697a849c28 ] |
| |
| When we accept a TCP connection and allocate an nvmet-tcp queue we should |
| make sure not to fully establish it or reference it as the connection may |
| be already closing, which triggers queue release work, which does not |
| fence against queue establishment. |
| |
| In order to address such a race, we make sure to check the sk_state and |
| contain the queue reference to be done underneath the sk_callback_lock |
| such that the queue release work correctly fences against it. |
| |
| Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver") |
| Reported-by: Elad Grupi <elad.grupi@dell.com> |
| Signed-off-by: Sagi Grimberg <sagi@grimberg.me> |
| Signed-off-by: Christoph Hellwig <hch@lst.de> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/nvme/target/tcp.c | 28 ++++++++++++++++++---------- |
| 1 file changed, 18 insertions(+), 10 deletions(-) |
| |
| diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c |
| index 577ce7d403ae9..8b0485ada315b 100644 |
| --- a/drivers/nvme/target/tcp.c |
| +++ b/drivers/nvme/target/tcp.c |
| @@ -1485,17 +1485,27 @@ static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue) |
| if (inet->rcv_tos > 0) |
| ip_sock_set_tos(sock->sk, inet->rcv_tos); |
| |
| + ret = 0; |
| write_lock_bh(&sock->sk->sk_callback_lock); |
| - sock->sk->sk_user_data = queue; |
| - queue->data_ready = sock->sk->sk_data_ready; |
| - sock->sk->sk_data_ready = nvmet_tcp_data_ready; |
| - queue->state_change = sock->sk->sk_state_change; |
| - sock->sk->sk_state_change = nvmet_tcp_state_change; |
| - queue->write_space = sock->sk->sk_write_space; |
| - sock->sk->sk_write_space = nvmet_tcp_write_space; |
| + if (sock->sk->sk_state != TCP_ESTABLISHED) { |
| + /* |
| + * If the socket is already closing, don't even start |
| + * consuming it |
| + */ |
| + ret = -ENOTCONN; |
| + } else { |
| + sock->sk->sk_user_data = queue; |
| + queue->data_ready = sock->sk->sk_data_ready; |
| + sock->sk->sk_data_ready = nvmet_tcp_data_ready; |
| + queue->state_change = sock->sk->sk_state_change; |
| + sock->sk->sk_state_change = nvmet_tcp_state_change; |
| + queue->write_space = sock->sk->sk_write_space; |
| + sock->sk->sk_write_space = nvmet_tcp_write_space; |
| + queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work); |
| + } |
| write_unlock_bh(&sock->sk->sk_callback_lock); |
| |
| - return 0; |
| + return ret; |
| } |
| |
| static int nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port, |
| @@ -1543,8 +1553,6 @@ static int nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port, |
| if (ret) |
| goto out_destroy_sq; |
| |
| - queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work); |
| - |
| return 0; |
| out_destroy_sq: |
| mutex_lock(&nvmet_tcp_queue_mutex); |
| -- |
| 2.27.0 |
| |