diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index f7a080ef03543e190b2475be811dd601d8b7c53d..47ae032f8d9779df696835554343d39fdd21001a 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -364,6 +364,9 @@ void __cpuinit xen_init_lock_cpu(int cpu)
 	int irq;
 	const char *name;
 
+	WARN(per_cpu(lock_kicker_irq, cpu) > 0, "spinlock on CPU%d exists on IRQ%d!\n",
+	     cpu, per_cpu(lock_kicker_irq, cpu));
+
 	name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
 	irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
 				     cpu,
@@ -383,6 +386,7 @@ void __cpuinit xen_init_lock_cpu(int cpu)
 void xen_uninit_lock_cpu(int cpu)
 {
 	unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
+	per_cpu(lock_kicker_irq, cpu) = -1;
 }
 
 void __init xen_init_spinlocks(void)