GDR: How to reg GPU memory which is allocated in another process to NIC

Gaming and Visualization Technologies General Topics & Other SDKs GPU - Hardware
1

We are trying to do something like the following

1.(Process A) allocate GPU Memory

2.(Process A) pass the handle of gpu memory generated by cudaIpcGetMemHandle to Process B

3.(Process B) get pointer of the same gpu memory using cudaIpcOpenMemHandle

4.(Process B) reg the pointer to NIC to enable GDR using ibv_reg_mr

The step 4 returns errno 14，how to fix this

Any advice on what to try would be greatly appreciated