diff --git a/src/udev/udevadm-monitor.c b/src/udev/udevadm-monitor.c
index 740344606d..64b1160d71 100644
--- a/src/udev/udevadm-monitor.c
+++ b/src/udev/udevadm-monitor.c
@@ -161,7 +161,8 @@ static int parse_argv(int argc, char *argv[]) {
                         if (r < 0)
                                 return r;
 
-                        subsystem = devtype = NULL;
+                        TAKE_PTR(subsystem);
+                        TAKE_PTR(devtype);
                         break;
                 }
                 case 't':