[libvirt] [PATCH] qemu_agent: fix deadlock in qemuProcessHandleAgentEOF

We shutdown a VM A by qemu agent,meanwhile an agent EOF of VM A happened, there's a chance that deadlock occurred: qemuProcessHandleAgentEOF in main thread A) priv->agent = NULL; //A happened before B //deadlock when we get agent lock which's held by worker thread qemuAgentClose(agent); qemuDomainObjExitAgent called by qemuDomainShutdownFlags in worker thread B) hasRefs = virObjectUnref(priv->agent); //priv->agent is NULL, return false if (hasRefs) virObjectUnlock(priv->agent); //agent lock will not be released here So I close agent first, then set priv->agent NULL to fix the deadlock. Signed-off-by: Wang Yufei <james.wangyufei(a)huawei.com&gt; Reviewed-by: Ren Guannan <renguannan(a)huawei.com&gt; --- src/qemu/qemu_process.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index f2586a1..8c9622e 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -150,11 +150,10 @@ qemuProcessHandleAgentEOF(qemuAgentPtr agent, goto unlock; } + qemuAgentClose(agent); priv->agent = NULL; virObjectUnlock(vm); - - qemuAgentClose(agent); return; unlock: -- 1.8.3.4