CUDA ToolKit 9.1: CUDA driver version is insufficient for CUDA runtime version

I followed exactly the linux installation guide several times to install cuda 9.1 but getting error when running ./deviceQuery

./deviceQuery Starting...

 CUDA Device Query (Runtime API) version (CUDART static linking)

cudaGetDeviceCount returned 35
-> CUDA driver version is insufficient for CUDA runtime version
Result = FAIL

I have

cuda-runtime-9-1 is already the newest version (9.1.85-1).
cuda-drivers is already the newest version (387.26-1).
$ nvidia-smi
Fri May  4 23:30:55 2018       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 390.48                 Driver Version: 390.48                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce 940MX       Off  | 00000000:02:00.0 Off |                  N/A |
| N/A   37C    P0    N/A /  N/A |    432MiB /  2004MiB |      3%      Default |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0      1092      G   /usr/lib/xorg/Xorg                           168MiB |
|    0      2717      G   compiz                                        50MiB |
|    0      2944      G   ...-token=96A2E858145FF6AAA83B5DF70E9F010B    38MiB |
|    0      3342      G   ...-token=C5993195008196AAAD306CA180F63FAA   171MiB |
+-----------------------------------------------------------------------------+
$ nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2017 NVIDIA Corporation
Built on Fri_Nov__3_21:07:56_CDT_2017
Cuda compilation tools, release 9.1, V9.1.85
$ cat /proc/driver/nvidia/version 
NVRM version: NVIDIA UNIX x86_64 Kernel Module  390.48  Thu Mar 22 00:42:57 PDT 2018
GCC version:  gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9)
$ ll /dev/ | grep nvidia
crwxrw-rw-   1 root root    195,     0 May  4 22:47 nvidia0
crwxrw-rw-   1 root root    195,   255 May  4 22:47 nvidiactl
crwxrw-rw-   1 root root    195,   254 May  4 22:47 nvidia-modeset
crwxrw-rw-   1 root root    237,     0 May  4 22:47 nvidia-uvm
$ uname -a
Linux vincent-ThinkPad 4.13.0-38-generic #43~16.04.1-Ubuntu SMP Wed Mar 14 17:48:43 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

What is wrong with my installation?

Thanks!