Process not running with MPS

Why process not running with MPS?

I enabled MPS using these command

export CUDA_VISIBLE_DEVICES=7
nvidia-smi -i 7 -c EXCLUSIVE_PROCESS
nvidia-cuda-mps-control -d

I run my program successfully at first time.

but at second,third time the program just hang on, it’s not work like below
it seems like the GPU doesn’t schedule the process.

The issue will be solved when I resart nvidia-cuda-mps-server,but again it’s not work after I run my program multiple times.

Is it a bug?