diff --git a/sys/kern/subr_smp.c b/sys/kern/subr_smp.c
--- a/sys/kern/subr_smp.c
+++ b/sys/kern/subr_smp.c
@@ -187,6 +187,7 @@
 }
 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL);
 
+/* Argument for 'td' must not be 'curthread'. */
 void
 forward_signal(struct thread *td)
 {
@@ -198,8 +199,8 @@
 	 * executing so that it executes ast().
 	 */
 	THREAD_LOCK_ASSERT(td, MA_OWNED);
-	KASSERT(TD_IS_RUNNING(td),
-	    ("forward_signal: thread is not TDS_RUNNING"));
+	KASSERT(TD_IS_RUNNING(td), ("%s: thread is not TDS_RUNNING", __func__));
+	KASSERT(td != curthread, ("%s: Thread is curthread", __func__));
 
 	CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc);
 
@@ -208,10 +209,6 @@
 	if (!forward_signal_enabled)
 		return;
 
-	/* No need to IPI ourself. */
-	if (td == curthread)
-		return;
-
 	id = td->td_oncpu;
 	if (id == NOCPU)
 		return;