diff --git a/chardev/char.c b/chardev/char.c
index c0cc52824b..f54dc3a862 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -333,7 +333,7 @@ static bool qemu_chr_is_busy(Chardev *s)
 {
     if (CHARDEV_IS_MUX(s)) {
         MuxChardev *d = MUX_CHARDEV(s);
-        return d->mux_cnt >= 0;
+        return d->mux_cnt > 0;
     } else {
         return s->be != NULL;
     }