Xen devel - Jan 2009 - system crashing while testing GPLPV drivers

I am rewriting the TX path in the GPLPV drivers and in its current form
I am readily able to crash the system (eg Dom0 and everything else
running) from DomU.

xen is 3.3.1, linux is at most a week behind the 3.3.1 release date.

My Windows DomU boots up, fails to get an IP address (yes, the TX path
is broken), and then a short time later the system has rebooted.

I don''t know exactly what is causing it, but I suspect that
I''m handing
netback some badly formed buffers or something and causing a bug check
in Dom0.

James

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Do you get a backtrace?

 -- Keir

On 26/01/2009 01:10, "James Harper"
<james.harper@bendigoit.com.au> wrote:
> I am rewriting the TX path in the GPLPV drivers and in its current form
> I am readily able to crash the system (eg Dom0 and everything else
> running) from DomU.
> 
> xen is 3.3.1, linux is at most a week behind the 3.3.1 release date.
> 
> My Windows DomU boots up, fails to get an IP address (yes, the TX path
> is broken), and then a short time later the system has rebooted.
> 
> I don''t know exactly what is causing it, but I suspect that
I''m handing
> netback some badly formed buffers or something and causing a bug check
> in Dom0.
> 
> James
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel


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> 
> Do you get a backtrace?
> 
I''m at home and the server is at work, so I have it set to
automatically
reboot. There is nothing in any logs after the reboot.

I have found that if I pass a zero length network tx buffer, I get a
''BUG: warning" of:

BUG: warning at
arch/x86_64/kernel/../../i386/kernel/pci-dma-xen.c:364/dma_map_single()
Call Trace:
<IRQ> [<ffffffff8026bfa0>] dma_map_single+0x4f/0x1a7
[<ffffffff880b2ab9>] :tg3:tg3_start_xmit_dma_bug+0x449/0x7d9
[<ffffffff803bc759>] __qdisc_run+0x102/0x1c8
[<ffffffff80230964>] dev_queue_xmit+0x1f1/0x30d
[<ffffffff882a3f04>] :bridge:br_dev_queue_push_xmit+0x18b/0x1b2

The line in question is just a warn on mapping a dma buffer of length
zero.
I suspect that the actual crash is going to be something similar.

James

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