nvmet-tcp: fixup hang in nvmet_tcp_listen_data_ready()

When the socket is closed while in TCP_LISTEN a callback is run to
flush all outstanding packets, which in turns calls
nvmet_tcp_listen_data_ready() with the sk_callback_lock held.
So we need to check if we are in TCP_LISTEN before attempting
to get the sk_callback_lock() to avoid a deadlock.

Link: https://lore.kernel.org/linux-nvme/CAHj4cs-zu7eVB78yUpFjVe2UqMWFkLk8p+DaS3qj+uiGCXBAoA@mail.gmail.com/
Tested-by:  Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index d5966d007ba3f1cf4fc7d84d936a3b2f4ce90ae1..549a4786d1c3dd7b6f5a0ec4ba3c89ce0f699fcb 100644 (file)
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -2004,14 +2004,13 @@ static void nvmet_tcp_listen_data_ready(struct sock *sk)
 
        trace_sk_data_ready(sk);
 
+       if (sk->sk_state != TCP_LISTEN)
+               return;
+
        read_lock_bh(&sk->sk_callback_lock);
        port = sk->sk_user_data;
-       if (!port)
-               goto out;
-
-       if (sk->sk_state == TCP_LISTEN)
+       if (port)
                queue_work(nvmet_wq, &port->accept_work);
-out:
        read_unlock_bh(&sk->sk_callback_lock);
 }