[Xen-users] Networking of domUs stops working after a few minutes

[Arne Klein <arne.klein@xxxxxxxxxx>]

Hello,

A few minutes after starting a domU, network access is no longer 
possible from and to it.
This does not always happen and is not easily reproducible, but seems to 
occur in all newly started instances of the same domU from some point in 
time onwards. However, also restarting the dom0 does not necessarily 
prevent the problem.
At the moment when the network in the domU completely stops working, 
there is the error message
[2178752.854380] vif vif-33-0 vif33.0: Guest Rx stalled
visible in dmesg in the dom0. The connection can already be limited a 
bit before of that.
It is sometimes possible to for example ping the domU for a longer time 
than pinging any host from the domU. Also pings may still be possible 
for a few minutes, while SSH sessions do no longer work. This all occurs 
before the "Guest Rx stalled" error.
Both dom0 and domU are Debian lenny installations. We tested the kernel 
version 3.16.7-ckt11-1+deb8u3 as well as 4.1.3-1~bpo8+1 on the dom0 as 
well as the domU. The problem happens with newly created domUs via 
'xen-create-image', as well as with older domUs which have been migrated 
from a debian wheezy dom0. It happens with the vif-route as well as the 
vif-bridge script in the domU configuration.
The xen hypervisor version is 4.4.1-9+deb8u1.

When the network stops working, the ARP tables are no longer filled on 
dom0 and domU, for example:
Address HWtype HWaddress Flags Mask Iface
1.2.3.4 (incomplete) vif33.0

Debugging with tcpdump in the minutes before the "Guest Rx stalled" 
error shows that packets sent from the domU reach the dom0, but the 
replies from dom0 do not arrive at the domU. For example pings or ARP 
requests show as being sent on dom0, but the corresponding entry never 
shows on the domU.
Thank you and best regards,
Arne Klein


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users