Function register_kernel_timer 

pub fn register_kernel_timer(
    deadline: MonotonicDeadline,
    callback: KernelTimerCallback,
) -> Result<KernelTimerHandle, TaskError>

Registers a task-context callback on the calling CPU’s monotonic clock base.

Callback ownership is allocated before IRQs are excluded. Hard IRQ only promotes the entry into the existing ktimers/%u service; the callback is invoked later without the deadline lock or an IRQ guard held.

Errors

Returns TaskError::UnsafeContext outside ordinary task context, TaskError::TimerCapacity when the per-CPU callback base is full, or a runtime/clockevent error without leaving a hidden registration behind.