diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index 5ad5272af7d8..da559a580de1 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -125,6 +125,8 @@ struct ktr_desc {
 	callout_t ktd_wakch;		/* delayed wakeup */
 	kcondvar_t ktd_sync_cv;
 	kcondvar_t ktd_cv;
+
+	bool ktd_callout_pending;
 };
 
 static void	ktrwrite(struct ktr_desc *, struct ktrace_entry *);
@@ -175,16 +177,24 @@ static void
 ktd_wakeup(struct ktr_desc *ktd)
 {
 
-	callout_stop(&ktd->ktd_wakch);
-	cv_signal(&ktd->ktd_cv);
+	KASSERT(mutex_owned(&ktrace_lock));
+	KASSERT(ktd->ktd_callout_pending || !callout_pending(&ktd->ktd_wakch));
+
+	ktd->ktd_callout_pending = false;
+	if (!callout_halt(&ktd->ktd_wakch, &ktrace_lock)) {
+		cv_signal(&ktd->ktd_cv);
+	}
 }
 
 static void
 ktd_callout(void *arg)
 {
+	struct ktr_desc *ktd = arg;
 
 	mutex_enter(&ktrace_lock);
-	ktd_wakeup(arg);
+	KASSERT(ktd->ktd_callout_pending);
+	ktd->ktd_callout_pending = false;
+	cv_signal(&ktd->ktd_cv);
 	mutex_exit(&ktrace_lock);
 }
 
@@ -390,11 +400,16 @@ ktraddentry(lwp_t *l, struct ktrace_entry *kte, int flags)
 		/* Schedule delayed wakeup */
 		if (ktd->ktd_qcount > ktd->ktd_delayqcnt)
 			ktd_wakeup(ktd);	/* Wakeup now */
-		else if (!callout_pending(&ktd->ktd_wakch))
+		else if (!callout_pending(&ktd->ktd_wakch)) {
+			KASSERT(!ktd->ktd_callout_pending);
+			ktd->ktd_callout_pending = true;
 			callout_reset(&ktd->ktd_wakch,
 			    ktd->ktd_flags & KTDF_INTERACTIVE ?
 			    ktd->ktd_intrwakdl : ktd->ktd_wakedelay,
 			    ktd_callout, ktd);
+		} else {
+			KASSERT(callout_pending(&ktd->ktd_wakch));
+		}
 	}
 
 skip_sync:
@@ -1025,6 +1040,7 @@ ktrace_common(lwp_t *curl, int ops, int facs, int pid, file_t **fpp)
 			nktd = kmem_alloc(sizeof(*nktd), KM_SLEEP);
 			TAILQ_INIT(&nktd->ktd_queue);
 			callout_init(&nktd->ktd_wakch, CALLOUT_MPSAFE);
+			nktd->ktd_callout_pending = false;
 			cv_init(&nktd->ktd_cv, "ktrwait");
 			cv_init(&nktd->ktd_sync_cv, "ktrsync");
 			nktd->ktd_flags = 0;
@@ -1409,7 +1425,10 @@ ktrace_thread(void *arg)
 		/* nothing, collision in KTROP_SET */
 	}
 
-	callout_halt(&ktd->ktd_wakch, &ktrace_lock);
+	KASSERT(!cv_has_waiters(&ktd->ktd_cv));
+	if (!callout_halt(&ktd->ktd_wakch, &ktrace_lock))
+		ktd->ktd_callout_pending = false;
+	KASSERT(!ktd->ktd_callout_pending);
 	callout_destroy(&ktd->ktd_wakch);
 	mutex_exit(&ktrace_lock);
 
@@ -1421,6 +1440,7 @@ ktrace_thread(void *arg)
 	 */
 	closef(fp);
 
+	KASSERT(!ktd->ktd_callout_pending);
 	cv_destroy(&ktd->ktd_sync_cv);
 	cv_destroy(&ktd->ktd_cv);