FreeBSD 11 Stable on a Xen :: bridge0 crashing server

[Andrey V. Elsukov]

On 20.01.2017 18:57, Trond Endrestøl wrote:
>> Here is the situation:
>> I have a VPS server from a well reputed provider (and they deserve the
>> reputation), running FreeBSD 11 stable x64 under Xen Full Virtualization
>> (HVM). I have the xn0 interface which is working fine. I intend to use VIMAGE,
>> so I compiled the kernel, added cloned_interface="bridge0" and restarted the
>> server. But as soon as I am attaching the xn0 to bridge0, the kernel is
>> panicking and the server restarting.
>> Any suggestion/pointer/test-instruction is highly appreciated.
>
> The code crashes at line 427 of sys/netinet/if_ether.c:
>
>   ARPSTAT_INC(txrequests);
>
> See
> https://svnweb.freebsd.org/base/stable/11/sys/netinet/if_ether.c?view=annotate#l427
>
> stable/11 has problems accounting the outgoing octets of any xn
> interface, although this isn't connected to your case.
>
> Just to rule out any uncertainty, try this patch:
>
> https://svnweb.freebsd.org/base?view=revision&revision=308126
>
> See PR 213439,
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213439
>
> Note, I'm not a developer nor a committer, just a humble sysadmin.

This problem is unrelated. ARP statistics is global and isn't related to 
some specific interface. IMHO, the kernel panics due to missing VNET 
context. As I see from the code in sys/dev/xen, it is not capable with 
VIMAGE.

-- 
WBR, Andrey V. Elsukov