qemuAgentClose and qemuAgentIO have race condition,
as follows:
main thread: second thread:
virEventPollRunOnce processSerialChangedEvent
virEventPollDispatchHandles
virMutexUnlock(&eventLoop.lock)
qemuAgentClose
virObjectLock(mon)
virEventRemoveHandle
VIR_FORCE_CLOSE(mon->fd)
virObjectUnlock(mon)
priv->agentError = false
qemuAgentIO
virObjectLock(mon)
mon->fd != fd --> error = true
qemuProcessHandleAgentError
priv->agentError = true
virObjectUnlock(mon)
virMutexLock(&eventLoop.lock)
qemuAgentClose set the mon->fd to '-1', and then qemuAgentIO
check the mon->fd not equals to fd that registered before.
qemuProcessHandleAgentError will be called to set
priv->agentError to 'true', then the priv->agentError is
always 'true' except restart libvirtd or restart
qemu-guest-agent process in guest. We can't send any
qemu-agent-command anymore even if qemuConnectAgent return
success later.
This is accidently occurs when hot-add-vcpu in windows2012.
virsh setvcpus ...
virsh qemu-agent-command $vm '{"execute":"guest-get-vcpus"}'
Reset the priv->agentError to 'false' when qemuConnectAgent sucess
to fix this problem.
Signed-off-by: Wang Yechao <wang.yechao...@zte.com.cn>
---
src/qemu/qemu_process.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 29b0ba1..4fbb955 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -269,6 +269,7 @@ qemuConnectAgent(virQEMUDriverPtr driver, virDomainObjPtr
vm)
virResetLastError();
}
+ priv->agentError = false;
return 0;
}
--
1.8.3.1
--
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