Re: netconsole regression w/ 8d8fc29d

[Rik van Riel <riel@redhat.com>]

On 06/15/2011 04:10 AM, Cong Wang wrote:
> 于 2011年06月15日 15:58, Rik van Riel 写道:
>> After commit 8d8fc29d02a33e4bd5f4fa47823c1fd386346093
>> (netpoll: disable netpoll when enslave a device), it is
>> no longer possible to use netconsole together with bridged
>> KVM guests.
>>
>> I can see why the change looked reasonable from a networking
>> point of view, but this has completely disabled netconsole
>> functionality for a common KVM use case.
>>
>> After the change, netconsole refuses to bind to eth0.
>>
>> Since the bridge interface does not support polling,
>> netconsole cannot use that, either.
>
>
> Bridge does support polling now. :) You can just setup
> netconsole on a bridge device.

This turns out to be mutually exclusive with attaching
virtual interfaces (for KVM guests) to a bridge.

If I start netconsole first, my KVM guests won't start.

If I start the KVM guests first, netconsole won't start,
and fails with these errors:

netconsole:: inserting netconsole module with arguments 
netconsole=6666@74.92.59.68/br0,514@74.92.59.66/00:13:72:17:4A:9C
kernel: [ 1020.927240] netconsole: local port 6666
kernel: [ 1020.927243] netconsole: local IP 74.92.59.68
kernel: [ 1020.927245] netconsole: interface 'br0'
kernel: [ 1020.927246] netconsole: remote port 514
kernel: [ 1020.927247] netconsole: remote IP 74.92.59.66
kernel: [ 1020.927252] netconsole: remote ethernet address 00:13:72:17:4a:9c
kernel: [ 1020.927256] (null):  doesn't support polling, aborting.
kernel: [ 1020.927258] netconsole: cleaning up
systemd[1]: netconsole.service: control process exited, code=exited status=1
systemd[1]: Unit netconsole.service entered failed state.

In short, I am still not able to use netconsole and bridged
KVM guests at the same time...

# brctl show
bridge name	bridge id		STP enabled	interfaces
br0		8000.0024e838995c	no		eth0
							vnet0
							vnet1
							vnet2


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