Re: [Qemu-devel] [PATCH v9 0/6] monitor: enable OOB by default

[Eric Blake <eblake@redhat.com>]

On 10/10/18 7:05 PM, Peter Xu wrote:

>> other than the command line that is hanging:
>>
>> /home/eblake/qemu/x86_64-softmmu/qemu-system-x86_64 -S -no-user-config
>> -nodefaults -nographic -machine none,accel=kvm:tcg -qmp
>> unix:/var/lib/libvirt/qemu/capabilities.monitor.sock,server,nowait -pidfile
>> /var/lib/libvirt/qemu/capabilities.pidfile -daemonize
>>
>> And I suspect it is the -daemonize that is causing the hang I'm seeing when
>> run by libvirt.
>>

> 
> It's very possible the daemonize thing, actually Wolfgang Bumiller has
> posted patches to fix this up (it's not the problem of this series,
> but it just exposed this to libvirt by the series since it only
> happens when oob and daemonize are both enabled).  The fixes are:
> 
>    [PATCH v2 0/2] delay monitor iothread creation
> 
> Since it cannot be applied cleanly onto this series, I resolved the
> conflicts and pushed a tree here in case you wanna try with these two
> extra patches applied:
> 
>    https://github.com/xzpeter/qemu/tree/test-oob

Technically, we should apply the patches in the opposite order 
(Wolfgang's first, then yours), so that bisection does not land on a 
known-bad hang situation.

> 
> Please feel free to test with libvirt again with that.
> 
> Thanks for playing with the tree and further investigation!  I will
> also mention this in the next version of cover letter (if there is one).

Confirmed that libvirt no longer hung with Wolfgang's patches added in.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org