I'm the developer of ocland (now I have a really nice collaborator!), and I detected that clSetUserEventStatus is failing when the status is changed several times. From the documentation:
CL_INVALID_OPERATION if the execution_status for event has already been changed by a previous call to clSetUserEventStatus.
But CL_SUCCESS is returned to me. I'm on Ubuntu 14.04, AMD Radeon HD 8330, driver version 13.35.1005-140312a-169199E. Is it properly working on more recent versions? Is it a new bug?
Thanks for reporting this. As I checked with latest driver, I got the same observation as yours. I'll file a bug report against it.
The issue is no longer reproducible with the latest 16.4.1 (16.15.2211.1001).