From 4c55770ca020aeab01bd9565265b1bbf9bc32cd8 Mon Sep 17 00:00:00 2001
From: Zhang Jiao <zhangjiao2_yewu@cmss.chinamobile.com>
Date: Thu, 17 Oct 2024 13:57:15 +0800
Subject: [PATCH] chardev/char: fix qemu_chr_is_busy() check
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cheery-pick from df12798f8791a929f4d7309f67a0f437c608e7fb

`mux_cnt` struct member never goes negative or decrements,
so mux chardev can be !busy only when there are no
frontends attached. This patch fixes the always-true
check.

Fixes: a4afa548fc6d ("char: move front end handlers in CharBackend")
Signed-off-by: Roman Penyaev <r.peniaev@gmail.com>
Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com>
Cc: qemu-devel@nongnu.org
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20241014152408.427700-2-r.peniaev@gmail.com>
Signed-off-by: Zhang Jiao <zhangjiao2_yewu@cmss.chinamobile.com>
---
 chardev/char.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/chardev/char.c b/chardev/char.c
index 996a024c7a..a830043908 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;
     }
-- 
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