Index: sys/kern/kern_timeout.c
===================================================================
--- sys/kern/kern_timeout.c	(revision 224955)
+++ sys/kern/kern_timeout.c	(working copy)
@@ -268,9 +268,11 @@ callout_cpu_switch(struct callout *c, struct callo
 	CC_LOCK_ASSERT(cc);
 
 	c->c_cpu = CPUBLOCK;
+	spinlock_enter();
 	CC_UNLOCK(cc);
 	new_cc = CC_CPU(new_cpu);
 	CC_LOCK(new_cc);
+	spinlock_exit();
 	c->c_cpu = new_cpu;
 	return (new_cc);
 }