From 0f32142c4a92c9aca7890f25e89b56973a906201 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 d9209ac6d2..74bb9613bc 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -316,7 +316,9 @@ 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