Index: kernel/generic/src/time/clock.c
===================================================================
--- kernel/generic/src/time/clock.c	(revision 111b9b97905c174ce8c3ed7e4e2a890da2be2d66)
+++ kernel/generic/src/time/clock.c	(revision b2ec5cfd5e00eac7963f5a84fb71f002ad79f1f0)
@@ -125,5 +125,5 @@
 	irq_spinlock_lock(&CPU->lock, false);
 	uint64_t now = get_cycle();
-	CPU->busy_cycles += now - CPU->last_cycle;
+	atomic_time_increment(&CPU->busy_cycles, now - CPU->last_cycle);
 	CPU->last_cycle = now;
 	irq_spinlock_unlock(&CPU->lock, false);