diff --git a/route/syscall.go b/route/syscall.go
index c211188b..5f69ea63 100644
--- a/route/syscall.go
+++ b/route/syscall.go
@@ -20,7 +20,7 @@ func sysctl(mib []int32, old *byte, oldlen *uintptr, new *byte, newlen uintptr)
 	} else {
 		p = unsafe.Pointer(&zero)
 	}
-	_, _, errno := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(p), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	_, _, errno := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(p), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), newlen)
 	if errno != 0 {
 		return error(errno)
 	}