diff --git a/sys/kern/kern_switch.c b/sys/kern/kern_switch.c
index eeed120d995d..399e3e9401da 100644
--- a/sys/kern/kern_switch.c
+++ b/sys/kern/kern_switch.c
@@ -502,8 +502,8 @@ maybe_preempt(struct thread *td)
 	 * to the new thread.
 	 */
 	ctd = curthread;
-	if (ctd->td_kse == NULL || ctd->td_kse->ke_thread != ctd)
-		return (0);
+	KASSERT ((ctd->td_kse != NULL && ctd->td_kse->ke_thread == ctd),
+	  ("thread has no (or wrong) sched-private part."));
 	pri = td->td_priority;
 	cpri = ctd->td_priority;
 	if (pri >= cpri || cold /* || dumping */ || TD_IS_INHIBITED(ctd) ||
diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c
index 62cde326ab45..60b13ce9a0f6 100644
--- a/sys/kern/sched_4bsd.c
+++ b/sys/kern/sched_4bsd.c
@@ -949,9 +949,10 @@ sched_add(struct thread *td, int flags)
 		 * the thread is unpinned
 		 * or pinned to another cpu,
 		 * and there are other available and idle CPUs.
-		 * if we are idle, then skip straight to preemption.
+		 * if we are idle, or it's an interrupt,
+		 * then skip straight to preemption.
 		 */
-		if ( (! idle) &&
+		if ( (! idle) && ((flags & SRQ_INTR) == 0) &&
 		    (idle_cpus_mask & ~(hlt_cpus_mask | me)) &&
 		    ( KSE_CAN_MIGRATE(ke) ||
 		      ke->ke_runq != &runq_pcpu[PCPU_GET(cpuid)])) {