From: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Date: Thu, 23 Jul 2020 08:02:59 +0000 (+0300)
Subject: qemu: avoid deadlock in qemuDomainObjStopWorker
X-Git-Tag: v6.8.0-rc1~276
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=860a999802d3c82538373bb3f314f92a2e258754;p=thirdparty%2Flibvirt.git

qemu: avoid deadlock in qemuDomainObjStopWorker

We are dropping the only reference here so that the event loop thread
is going to be exited synchronously. In order to avoid deadlocks we
need to unlock the VM so that any handler being called can finish
execution and thus even loop thread be finished too.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index b1884b6c84..0ed132a829 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1722,11 +1722,21 @@ void
 qemuDomainObjStopWorker(virDomainObjPtr dom)
 {
     qemuDomainObjPrivatePtr priv = dom->privateData;
+    virEventThread *eventThread;
 
-    if (priv->eventThread) {
-        g_object_unref(priv->eventThread);
-        priv->eventThread = NULL;
-    }
+    if (!priv->eventThread)
+        return;
+
+    /*
+     * We are dropping the only reference here so that the event loop thread
+     * is going to be exited synchronously. In order to avoid deadlocks we
+     * need to unlock the VM so that any handler being called can finish
+     * execution and thus even loop thread be finished too.
+     */
+    eventThread = g_steal_pointer(&priv->eventThread);
+    virObjectUnlock(dom);
+    g_object_unref(eventThread);
+    virObjectLock(dom);
 }