diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -1072,7 +1072,7 @@
 	_mtx_release_lock_quick(m);
 	ts = turnstile_lookup(&m->lock_object);
 	if (__predict_false(ts == NULL)) {
-		panic("got NULL turnstile on mutex %p v %zx", m, v);
+		panic("got NULL turnstile on mutex %p v %p", m, (void *)v);
 	}
 	if (LOCK_LOG_TEST(&m->lock_object, opts))
 		CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c
--- a/sys/kern/kern_rwlock.c
+++ b/sys/kern/kern_rwlock.c
@@ -843,8 +843,8 @@
 		 */
 		ts = turnstile_lookup(&rw->lock_object);
 		if (__predict_false(ts == NULL)) {
-			panic("got NULL turnstile on rwlock %p passedv %zx v %zx",
-			    rw, passedv, v);
+			panic("got NULL turnstile on rwlock %p passedv %p v %p",
+			    rw, (void *)passedv, (void *)v);
 		}
 		turnstile_broadcast(ts, queue);
 		turnstile_unpend(ts);
@@ -1288,8 +1288,8 @@
 
 	ts = turnstile_lookup(&rw->lock_object);
 	if (__predict_false(ts == NULL)) {
-		panic("got NULL turnstile on rwlock %p passedv %zx v %zx", rw,
-		    passedv, v);
+		panic("got NULL turnstile on rwlock %p passedv %p v %p", rw,
+		    (void *)passedv, (void *)v);
 	}
 	turnstile_broadcast(ts, queue);
 	turnstile_unpend(ts);