On Wed, 2022-07-20 at 06:50 -0400, Sam Varshavchik wrote:
Patrick O'Callaghan writes:
> On Wed, 2022-07-20 at 13:20 +1000, Eyal Lebedinsky wrote:
> >
> >
> > On 19/07/2022 14.39, Eyal Lebedinsky wrote:
> > >
> > > On 19/07/2022 07.42, Sam Varshavchik wrote:
> > > > Am I the only one lucky enough to have kernel-5.18.11-
> > > > 200.fc36.x86_64 crash reliably, on particular hardware, after
> > > > starting a VM in virt-manager?
> > > >
> > > > At least I think it's a crash. One second after a VM start
> > > > it's
> > > > brick-city. Display frozen, no response from the network.
> > > > I've
> > > > got nothing: after a reboot there's nothing in journalctl -r
> > > > -b -
> > > > 1. This brings up fond memories -- ages ago I had a null
> > > > modem
> > > > adapter hooked up to a serial port, the kernel configured for
> > > > a
> > > > serial console, thusly I was able to capture OOPSes over the
> > > > serial console, in situations like these.
> > > >
> > > > But, these days, no more RS-232 ports. I dimly recall that a
> > > > USB-
> > > > serial option is possible; but I don't have any of that in
> > > > any
> > > > case.
> > > >
> > > > Anyway, reverting to 5.18.9 made this VM happy, and my VMs on
> > > > another hardware, also running the same kernel, are also
> > > > fine.
> > > > But, 5.18.11 gets reliably clusterfarked by qemu on at least
> > > > on
> > > > some hardware combinations. I wish I had more useful data
> > > > points,
> > > > but I've got nuthin' worth putting into Bugzilla.
> > >
> > > Just a data point for you.
> > >
> > > I run 5.18.11-200.fc36.x86_64 on the host and on the guest
> > > (KVM).
> > > No crashes so far.
> > > However, sound is now broken, highly distorted, so maybe there
> > > is
> > > something bad with this kernel?
> > >
> > > You bay want to set rsyslog to log to the host, hoping to catch
> > > messages that did not make it to
> > > the guests fs. I have all my machines log to my server (which
> > > is
> > > the host too).
> > >
> > > A special, long incantation is appended to /etc/rsyslog.conf
> > > (on
> > > the guest).
> > > On the host I Provided TCP/UDP syslog reception in the same
> > > conf
> > > file.
> >
> > I now changed the guest machine from "sound ac97" to "sound
ich6"
> > and
> > sound now works OK.
> > The old setup was OK for a very long time.
> >
> > It is a worry when a stable setup stops working, so the OP may
> > consider trying different
> > guest settings.
>
> IIRC ich6 has been preferred to ac97 for quite a long time now.
I had mine set to use ich9 and ich6 made no difference to me, it's
still
scratchy. It looks to me more fundamental than emulated audio, the
entire VM
became sluggish with the 5.18 kernel.
Regarding sound, there are some suggestions here:
https://juho.tykkala.fi/Pulseaudio-and-latency#positive-effect-on-latency
However I haven't tried the latest kernel myself so can't really
comment.
poc