[PATCH 1/4] qemu_agent: Rework domain object locking when opening agent
Just like qemuMonitorOpen(), hold the domain object locked
throughout the whole time of qemuConnectAgent() and unlock it
only for a brief time of actual connect() (because this is the
only part that has a potential of blocking).
The reason is that qemuAgentOpen() does access domain object
(well, its privateData) AND also at least one argument (@context)
depends on domain object. Accessing these without the lock is
potentially dangerous.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1845468#c12
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/qemu/qemu_agent.c | 3 +++
src/qemu/qemu_process.c | 4 ----
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c
index 5f421be6f6..166cfaf485 100644
--- a/src/qemu/qemu_agent.c
+++ b/src/qemu/qemu_agent.c
@@ -704,7 +704,10 @@ qemuAgentOpen(virDomainObj *vm,
goto cleanup;
}
+ virObjectUnlock(vm);
agent->fd = qemuAgentOpenUnix(config->data.nix.path);
+ virObjectLock(vm);
+
if (agent->fd == -1)
goto cleanup;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index d5f8a47ac2..d2ea9b55fe 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -238,16 +238,12 @@ qemuConnectAgent(virQEMUDriver *driver, virDomainObj *vm)
* deleted while the agent is active */
virObjectRef(vm);
- virObjectUnlock(vm);
-
agent = qemuAgentOpen(vm,
config->source,
virEventThreadGetContext(priv->eventThread),
&agentCallbacks,
virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_VSERPORT_CHANGE));
- virObjectLock(vm);
-
if (agent == NULL)
virObjectUnref(vm);
--
2.32.0