By default, the kernel checks stacks in idle. It sees if they are overflowed. If they are, an error occurs. So it looks like you just happen to stop the target during a check. If they is nothing going on in the system and you halt the target, the likelihood of being in this function is pretty high.
Look at ROV to see the status of the Tasks in your system. I expect they will be blocked on something (except Idle).
Todd
