[libvirt] [PATCH] qemu: Qemu process unexpectedly killed in repeated reboot

[Michal Privoznik]

On 11/30/18 9:53 AM, Wang King wrote:
> The issue occurs when I make repeated calls to virDomainReboot with
> VIR_DOMAIN_REBOOT_DEFAULT flag. In the first call to reboot domain,
> the qemu driver chose ACPI path, and set priv->fakeReboot to true.
> Then in a second call, qemu driver chose agent to reboot which set
> fakeReboot to false. But because the guest already responded to ACPI
> shut down, libvirtd daemon will process a SHUTDOWN event in
> qemuProcessShutdownOrReboot and checks priv->fakeReboot. Since the
> fakeReboot flag is now false, qemu process is unexpectedly killed.
> 

This sounds fishy. Looking at the code libvirt decides whether to use
agent or ACPI based on:

a) flags (but since you're passing 0 this is out of the picture),
b) guest agent being available,

This means that agent must have connected between two virDomainReboot()
calls. Otherwise libvirt would make the same choice.

> I have no idea how to fix it.

Well, the qemuDomainSetFakeReboot(false) call was added in b0c144c5792
which points to:

  https://www.redhat.com/archives/libvir-list/2015-April/msg00732.html

I think the patch proposed there is actually right and not the one that
was merged.

Michal