Problems in allocation memory some time cudaMallocHost block the system

I’ve some trouble in allocating resources. I’m working with a S1070 (4 devices) and I’m not longer able to use some of the devices. Even when performing a cudaMallocHost the program blocks. On the other devices everything goes fine.
It seems the allocated resources have not been deallocated (even after terminating the program). May it be? If this is the case, is there any command to free all the dead resources allocated by that device?
(the crushing code is simply a cudaSetDevice followed by a cudaMallocHost)