Terminating the host process can cause the machine to crash/freeze when OpenCL is running. The BSP requires the host user process to stay alive during certain operations such as DMA transfers. If the user terminates the host process while such operations are active, the operating system will crash. This means users of the affected BSPs should avoid things such as: i) hitting ctrl-C; ii) assertions; iii) calling exit(); iv) any abnormal termination in the host programs (null dereference, bus error, uncaught exception, etc).
Do not kill or quit applications while running. To debug asserts/segfaults/uncaught exceptions/etc. switch to using all blocking calls in your host program and calling clFinish immediately after enqueuing any OpenCL work into queues. Once the abnormal termination has been identified and fixed, revert back to non-blocking calls and reduce clFinish call sites to only when the CPU needs to synchronize with the FPGA.