diff --git a/kernel/spinlock/spinlock.c b/kernel/spinlock/spinlock.c
index 8624003..26ad096 100644
--- a/kernel/spinlock/spinlock.c
+++ b/kernel/spinlock/spinlock.c
@@ -6,8 +6,8 @@
 
 #define SPINLOCK_HINT() asm volatile("pause")
 
-struct {
-  uint64_t irq_flags;
+static struct {
+  volatile uint64_t irq_flags;
   atomic_int irq_nest;
 } IRQ_CTX = {0};