diff --git a/arch/arm64/src/common/arm64_cpustart.c b/arch/arm64/src/common/arm64_cpustart.c
index 12b2b73492..0748813f8f 100644
--- a/arch/arm64/src/common/arm64_cpustart.c
+++ b/arch/arm64/src/common/arm64_cpustart.c
@@ -212,6 +212,15 @@ int up_cpu_start(int cpu)
   sched_note_cpu_start(this_task(), cpu);
 #endif
 
+#ifdef CONFIG_STACK_COLORATION
+  /* If stack debug is enabled, then fill the stack with a
+   * recognizable value that we can use later to test for high
+   * water marks.
+   */
+
+  arm64_stack_color(g_cpu_idlestackalloc[cpu], SMP_STACK_SIZE);
+#endif
+
   cpu_ready_flag = 0;
   arm64_start_cpu(cpu, (char *)g_cpu_idlestackalloc[cpu], SMP_STACK_SIZE,
                   arm64_smp_init_top);