Xen users - Apr 2008 - Xen 3.2 and Ubuntu Hardy with Linux kernel 2.6.24

Hi everyone,

Myself and some other Ubuntu Linux server users have noticed a difficult 
problem attempting to run a Xen DomU using a Linux 2.6.24 kernel as 
supplied within Ubuntu hardy.  The main symptom exhibited is that 
network packets sent over the network bridge exit the DomU and are seen 
by the Dom0, but when replies are sent back by the Dom0 to the DomU the 
replies never appear within the DomU.

The symptoms and attempts at trying to fix it can be seen by looking at 
the bug within launchpad:

https://bugs.launchpad.net/ubuntu/+source/xen-3.2/+bug/204010

It seems odd to me that Xen DomU support has been merged for 32-bit 
support in Linux mainline, but yet when attempting to run kernels since 
the merge we appear to have real problems with xennet processing inbound 
packets.

I''m yet to confirm that I have the same problem with a patched 2.6.23 
kernel, but when I boot a 2.6.22 kernel from gutsy within my DomU 
instances; everything works just fine.

It seems to me that there''s some real problem with xennet within the 
2.6.24 kernel, and I would like to debug it.  I''ve started delving into
the O''Reilly book on Linux Device Drivers, but is there any pointers or
assistance anyone here could render with attempting to isolate this problem?

Prior to my upgrade to Hardy and Xen 3.2 I''ve been running Xen 3.0.3 
with Ubuntu Dapper 6.06 on 2.6.18 with no troubles whatsoever.

Thanks in advance,
Mark.

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Hi All,

We think we have narrowed it down to the frontend driver in the domU,
since pings or dhcp requests go out and replies are sent back, but are
not accepted/read by the domU.

It is like the domU can''t read from the network.

Basically, I would like to be able to some more visibility into the
problem so that we can either fix it or let the Ubuntu developers know
what the problem is.

Any ideas on how to get some more visibility into the driver?

I will also hang out on ##xen on freenode and #xen on oftc as much as
possible to try to get some ideas.


The bug info is at:

http://tinyurl.com/yv53nw

OR

https://bugs.launchpad.net/ubuntu/+source/xen-3.2/+bug/204010



Thanks,
Todd

On Tue, Apr 1, 2008 at 5:50 AM, Mark Goldfinch <xen-users@g.org.nz>
wrote:
> Hi everyone,
>
>  Myself and some other Ubuntu Linux server users have noticed a difficult
> problem attempting to run a Xen DomU using a Linux 2.6.24 kernel as
supplied
> within Ubuntu hardy.  The main symptom exhibited is that network packets
> sent over the network bridge exit the DomU and are seen by the Dom0, but
> when replies are sent back by the Dom0 to the DomU the replies never appear
> within the DomU.
>
>  The symptoms and attempts at trying to fix it can be seen by looking at
the
> bug within launchpad:
>
>  https://bugs.launchpad.net/ubuntu/+source/xen-3.2/+bug/204010
>
>  It seems odd to me that Xen DomU support has been merged for 32-bit
support
> in Linux mainline, but yet when attempting to run kernels since the merge
we
> appear to have real problems with xennet processing inbound packets.
>
>  I''m yet to confirm that I have the same problem with a patched
2.6.23
> kernel, but when I boot a 2.6.22 kernel from gutsy within my DomU
instances;
> everything works just fine.
>
>  It seems to me that there''s some real problem with xennet within
the 2.6.24
> kernel, and I would like to debug it.  I''ve started delving into
the
> O''Reilly book on Linux Device Drivers, but is there any pointers
or
> assistance anyone here could render with attempting to isolate this
problem?
>
>  Prior to my upgrade to Hardy and Xen 3.2 I''ve been running Xen
3.0.3 with
> Ubuntu Dapper 6.06 on 2.6.18 with no troubles whatsoever.
>
>  Thanks in advance,
>  Mark.
>
>  _______________________________________________
>  Xen-users mailing list
>  Xen-users@lists.xensource.com
>  http://lists.xensource.com/xen-users
>
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