text: Title: Traning process get stuck at the first and fails to lauch
  Body: Hi there,
  
  I am using 
  `Ubuntu 18.04`
  `Tensorflow 1.15`
  `Cuda 10.0`
  `cuDNN 7.6.5`
  
  The `tf.test.is_gpu_available()` returns True.
  
  The whole program just gets stuck when I try to train the model no matter how small the model is. 
  
  Sometime after waiting for minutes I got the exception 
  `InternalError: (0) Internal: Blass GEMM launch failed`
  I know this error occurs when there are multiple sessions running at the same time but I just have exact one session. 
  
  I have been tortured for days, can someone give me some advice on it?