diff --git a/chardev/char.c b/chardev/char.c
index 996a024c7a2cdb9f59e13d92c4da15fc2cf0acdb..a830043908d15e0ec391be2151b4038b7ac16480 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -321,7 +321,7 @@ 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;
     }