vt_list = &per_cpu(virt_cpu_timer, timer->cpu);
        spin_lock_irqsave(&vt_list->lock, flags);
 
-       if (timer->cpu != smp_processor_id())
-               printk("internal_add_vtimer: BUG, running on wrong CPU");
+       BUG_ON(timer->cpu != smp_processor_id());
 
        /* if list is empty we only have to set the timer */
        if (list_empty(&vt_list->list)) {
        put_cpu();
 }
 
-static inline int prepare_vtimer(struct vtimer_list *timer)
+static inline void prepare_vtimer(struct vtimer_list *timer)
 {
-       if (!timer->function) {
-               printk("add_virt_timer: uninitialized timer\n");
-               return -EINVAL;
-       }
-
-       if (!timer->expires || timer->expires > VTIMER_MAX_SLICE) {
-               printk("add_virt_timer: invalid timer expire value!\n");
-               return -EINVAL;
-       }
-
-       if (vtimer_pending(timer)) {
-               printk("add_virt_timer: timer pending\n");
-               return -EBUSY;
-       }
-
+       BUG_ON(!timer->function);
+       BUG_ON(!timer->expires || timer->expires > VTIMER_MAX_SLICE);
+       BUG_ON(vtimer_pending(timer));
        timer->cpu = get_cpu();
-       return 0;
 }
 
 /*
        struct vtimer_list *timer;
 
        timer = (struct vtimer_list *)new;
-
-       if (prepare_vtimer(timer) < 0)
-               return;
-
+       prepare_vtimer(timer);
        timer->interval = 0;
        internal_add_vtimer(timer);
 }
        struct vtimer_list *timer;
 
        timer = (struct vtimer_list *)new;
-
-       if (prepare_vtimer(timer) < 0)
-               return;
-
+       prepare_vtimer(timer);
        timer->interval = timer->expires;
        internal_add_vtimer(timer);
 }
        unsigned long flags;
        int cpu;
 
-       if (!timer->function) {
-               printk("mod_virt_timer: uninitialized timer\n");
-               return  -EINVAL;
-       }
-
-       if (!expires || expires > VTIMER_MAX_SLICE) {
-               printk("mod_virt_timer: invalid expire range\n");
-               return -EINVAL;
-       }
+       BUG_ON(!timer->function);
+       BUG_ON(!expires || expires > VTIMER_MAX_SLICE);
 
        /*
         * This is a common optimization triggered by the
        cpu = get_cpu();
        vt_list = &per_cpu(virt_cpu_timer, cpu);
 
+       /* check if we run on the right CPU */
+       BUG_ON(timer->cpu != cpu);
+
        /* disable interrupts before test if timer is pending */
        spin_lock_irqsave(&vt_list->lock, flags);
 
                return 0;
        }
 
-       /* check if we run on the right CPU */
-       if (timer->cpu != cpu) {
-               printk("mod_virt_timer: running on wrong CPU, check your code\n");
-               spin_unlock_irqrestore(&vt_list->lock, flags);
-               put_cpu();
-               return -EINVAL;
-       }
-
        list_del_init(&timer->entry);
        timer->expires = expires;