diff --git a/src/core/killall.c b/src/core/killall.c
index 3dde3033fa3..37c645538cb 100644
--- a/src/core/killall.c
+++ b/src/core/killall.c
@@ -29,7 +29,7 @@ static bool ignore_proc(pid_t pid, bool warn_rootfs) {
         int r;
 
         /* We are PID 1, let's not commit suicide */
-        if (pid == 1)
+        if (pid <= 1)
                 return true;
 
         /* Ignore kernel threads */