[libvirt] [PATCH] Fix potential deadlock when agent is closed

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; If the qemuAgentClose method is called from a place which holds the domain lock, it is theoretically possible to get a deadlock in the agent destroy callback. This has not ben observed, but the equivalent code in the QEMU monitor destroy callback has seen a deadlock. Remove the redundant locking while unrefing the object and the bogus assignment Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/qemu/qemu_process.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index c8c188a..42da617 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -129,7 +129,8 @@ qemuProcessHandleAgentEOF(qemuAgentPtr agent, virDomainObjLock(vm); priv = vm->privateData; - priv->agent = NULL; + if (priv->agent == agent) + priv->agent = NULL; virDomainObjUnlock(vm); qemuDriverUnlock(driver); @@ -167,16 +168,9 @@ qemuProcessHandleAgentError(qemuAgentPtr agent ATTRIBUTE_UNUSED, static void qemuProcessHandleAgentDestroy(qemuAgentPtr agent, virDomainObjPtr vm) { - qemuDomainObjPrivatePtr priv; - VIR_DEBUG("Received destroy agent=%p vm=%p", agent, vm); - virDomainObjLock(vm); - priv = vm->privateData; - if (priv->agent == agent) - priv->agent = NULL; - if (virObjectUnref(vm)) - virDomainObjUnlock(vm); + virObjectUnref(vm); } -- 1.7.11.2