diff --git a/sys/compat/freebsd32/syscalls.master b/sys/compat/freebsd32/syscalls.master
index 5cfd0c83073d..2a421ddbf001 100644
--- a/sys/compat/freebsd32/syscalls.master
+++ b/sys/compat/freebsd32/syscalls.master
@@ -721,8 +721,8 @@
 431	AUE_NULL	NOPROTO	{ void thr_exit(long *state); }
 432	AUE_NULL	NOPROTO	{ int thr_self(long *id); }
 433	AUE_NULL	NOPROTO	{ int thr_kill(long id, int sig); }
-434	AUE_NULL	NOPROTO	{ int _umtx_lock(struct umtx *umtx); }
-435	AUE_NULL	NOPROTO	{ int _umtx_unlock(struct umtx *umtx); }
+434	AUE_NULL	STD	{ int freebsd32_umtx_lock(struct umtx *umtx); }
+435	AUE_NULL	STD	{ int freebsd32_umtx_unlock(struct umtx *umtx); }
 436	AUE_NULL	NOPROTO	{ int jail_attach(int jid); }
 437	AUE_EXTATTR_LIST_FD	UNIMPL	extattr_list_fd
 438	AUE_EXTATTR_LIST_FILE	UNIMPL	extattr_list_file
diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c
index 0cff693fffd9..4c7f9d7bc38c 100644
--- a/sys/kern/kern_umtx.c
+++ b/sys/kern/kern_umtx.c
@@ -2303,6 +2303,20 @@ _umtx_op(struct thread *td, struct _umtx_op_args *uap)
 
 #ifdef COMPAT_IA32
 
+int
+freebsd32_umtx_lock(struct thread *td, struct freebsd32_umtx_lock_args *uap)
+    /* struct umtx *umtx */
+{
+	return (do_lock_umtx32(td, (uint32_t *)uap->umtx, td->td_tid, NULL));
+}
+
+int
+freebsd32_umtx_unlock(struct thread *td, struct freebsd32_umtx_unlock_args *uap)
+    /* struct umtx *umtx */
+{
+	return (do_unlock_umtx32(td, (uint32_t *)uap->umtx, td->td_tid));
+}
+
 struct timespec32 {
 	u_int32_t tv_sec;
 	u_int32_t tv_nsec;