diff --git a/[refs] b/[refs]
index 853a19e9de82..1024c9c40cb0 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ef35a4e6d9eef3bd904b8c6b85618a2e878e801e
+refs/heads/master: cb9c6f15f318aa3aeb62fe525aa5c6dcf6eee159
diff --git a/trunk/arch/x86/xen/spinlock.c b/trunk/arch/x86/xen/spinlock.c
index f7a080ef0354..47ae032f8d97 100644
--- a/trunk/arch/x86/xen/spinlock.c
+++ b/trunk/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)