Squelch 'eof from qemu monitor' error on normal VM shutdown

[Jim Fehlig]

On 9/29/21 21:29, Jim Fehlig wrote:
> Hi All,
> 
> Likely Christian received a bug report that motivated commit aeda1b8c56, which 
> was later reverted by Michal with commit 72adaf2f10. In the past, I recall being 
> asked about "internal error: End of file from qemu monitor" on normal VM 
> shutdown and gave a hand wavy response using some of Michal's words from the 
> revert commit message.
> 
> I recently received a bug report (sorry, but no public link) from a concerned 
> user about this error and wondered if there is some way to improve it? I went 
> down some dead ends before circling back to Christian's patch. When rebased to 
> latest master, I cannot reproduce the hangs reported by Michal [1]. Perhaps 
> Nikolay's series to resolve hangs/crashes of libvirtd [2] has now made 
> Christian's patch viable?

Hmm, Nikolay's series improves thread management at daemon shutdown and doesn't 
touch VM shutdown logic. But there has been some behavior change from the time 
aeda1b8c56 was committed (3.4.0 dev cycle) to current git master. At least I 
don't see libvirtd hanging when running Michal's test on master + rebased 
aeda1b8c56.

Regards,
Jim

> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1536461
> [2] https://listman.redhat.com/archives/libvir-list/2020-July/msg01606.html