Re: Xen 4.18/ARM64 on Raspberry Pi 4B: VLAN traffic crashing Dom0

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Am 11.10.2023 um 10:55 schrieb Paul Leiber:
> On 16.09.2023 13:26, reijo.korhonen@xxxxxxxxx wrote:
> > On Thu, 2023-09-07 at 18:41 +0200, Paul Leiber wrote:
> > > However, as soon as I remotely access the zabbix web interface, the
> > >
> > > complete system (DomUs and Dom0) becomes unresponsive and reboots
> > > after
> > >
> > > a couple of seconds. This is reliably reproducable.
> > >
> > >
> > >
> > > I didn't see any error message in any log (zabbix, DomU syslog, Dom0
> > >
> > > syslog) except for the following lines immediately before the system
> > >
> > > reboots on the Xen serial console:
> > >
> > >
> > >
> > > (XEN) Watchdog timer fired for domain 0
> > >
> > > (XEN) Hardware Dom0 shutdown: watchdog rebooting machine
> > Hmm.. Here you have a hint, how to study this issue. Seems, that this
> > is not Xe, issue, but it is watchdog issue. Your should set watchdog to
> > log, why it is rebooting machine.
> >
> > You can also set or edit watchdog to do something else than rebooting
> > machine, because rebooting does not help your study.
> I tried to dig deeper into the cause for the watchdog triggering. 
> However, I didn't find any useful documentation on the web on how the 
> watchdog works or how to enable logging. Can anybody direct me to useful 
> information on the Xen watchdog, please?
> > Maybe it could also be helpful set your system to pure VLAN system
> > without Xen at all, but set system somehow to run same kind apps your
> > run with Xen and zabbix web interface. Maybe running Web server is
> > enough to study your VLAN1 and VLAN2. When your are sure, that VLAN1
> > and VLAN2 settings are OK and VLAN itself work with Raspberry OK, it is
> > much easier to continue with Xen and zabbix.
> I booted the system without Xen and set it up to use the VLAN 20 bridge 
> (the same that leads to a reboot when using it in the DomU) as primary 
> network interface. Everything seems to be working, I could download 
> large files from the internet without any problem. Next step is then to 
> follow your advice reproduce the Zabbix setup (sigh).
Setting up Zabbix on the base debian system (which in Xen setup would be 
Dom0) showed that the same setup (VLANs 10 and 20, bridges 1 and 2, 
using bridge 2 as interface for Zabbix) without Xen is working reliably, 
no reboots. This points to some Xen component being the root cause.
I'm out of ideas, I'm taking this to xen-devel now.

Paul