From baaf85d9c8b304c6cc95a892fc23962e8175a817 Mon Sep 17 00:00:00 2001
From: Peng Liang <liangpeng10@huawei.com>
Date: Wed, 24 Feb 2021 19:28:23 +0800
Subject: [PATCH] qemu: Add missing lock in qemuProcessHandleMonitorEOF

qemuMonitorUnregister will be called in multiple threads (e.g. threads
in rpc worker pool and the vm event thread).  In some cases, it isn't
protected by the monitor lock, which may lead to call g_source_unref
more than one time and a use-after-free problem eventually.

Add the missing lock in qemuProcessHandleMonitorEOF (which is the only
position missing lock of monitor I found).

Suggested-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_process.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 6b9f6fb860..9701bb398b 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -315,7 +315,9 @@ qemuProcessHandleMonitorEOF(qemuMonitorPtr mon,
     /* We don't want this EOF handler to be called over and over while the
      * thread is waiting for a job.
      */
+    virObjectLock(mon);
     qemuMonitorUnregister(mon);
+    virObjectUnlock(mon);
 
     /* We don't want any cleanup from EOF handler (or any other
      * thread) to enter qemu namespace. */
-- 
2.27.0

