Index: sys/kern/kern_lock.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_lock.c,v
retrieving revision 1.155
diff -u -p -r1.155 kern_lock.c
--- sys/kern/kern_lock.c	14 Sep 2013 20:24:22 -0000	1.155
+++ sys/kern/kern_lock.c	13 Feb 2015 12:38:57 -0000
@@ -78,7 +78,8 @@ assert_sleepable(void)
 	} while (pctr != lwp_pctr());
 
 	reason = NULL;
-	if (idle && !cold) {
+	if (idle && !cold &&
+	    kcpuset_isset(kcpuset_running, cpu_index(curcpu()))) {
 		reason = "idle";
 	}
 	if (cpu_intr_p()) {