From 2e572baf659f5a457c876c6b2d02a217afb401c5 Mon Sep 17 00:00:00 2001
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Date: Wed, 10 Nov 2021 11:38:00 +0100
Subject: [PATCH] ui/vnc-clipboard: fix adding notifier twice
vnc_server_cut_text_caps() is not guaranteed to be called only once.
If it called twice, we finally call notifier_list_add() twice with same
element. Which leads to loopback QLIST. So, on next
notifier_list_notify() we'll loop forever and QEMU stuck.
So, let's only register new notifier if it's not yet registered.
Note, that similar check is used in vdagent_chr_recv_caps() (before
call qemu_clipboard_peer_register()), and also before
qemu_clipboard_peer_unregister() call in vdagent_disconnect() and in
vnc_disconnect_finish().
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211110103800.2266729-1-vsementsov@virtuozzo.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
ui/vnc-clipboard.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/ui/vnc-clipboard.c b/ui/vnc-clipboard.c
index 9f077965d0..67284b556c 100644
--- a/ui/vnc-clipboard.c
+++ b/ui/vnc-clipboard.c
@@ -316,8 +316,10 @@ void vnc_server_cut_text_caps(VncState *vs)
caps[1] = 0;
vnc_clipboard_send(vs, 2, caps);
- vs->cbpeer.name = "vnc";
- vs->cbpeer.update.notify = vnc_clipboard_notify;
- vs->cbpeer.request = vnc_clipboard_request;
- qemu_clipboard_peer_register(&vs->cbpeer);
+ if (!vs->cbpeer.update.notify) {
+ vs->cbpeer.name = "vnc";
+ vs->cbpeer.update.notify = vnc_clipboard_notify;
+ vs->cbpeer.request = vnc_clipboard_request;
+ qemu_clipboard_peer_register(&vs->cbpeer);
+ }
}
--
2.30.2