Re: Recent change to if_xennet_xenbus.c broke domU with root on NFS?

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 18.04.2011 22:14, Urban Boquist wrote:
> Hi all,
> 
> I just upgraded an oldish netbsd-5 domU to a more recent version and
> it now panics immediately on boot. After some digging around I found
> that it works if I back out this change to if_xennet_xenbus.c:
> 
> ---------------------------- revision 1.42 date: 2010/10/16 00:12:08;
> author: jym;  state: Exp;  lines: +6 -13 Features (like
> feature-rx-copy) are set during XenbusStateInitWait in backend. So
> delay xennet_xenbus_resume() up to notification of backend state
> change.

> I get the same behaviour both with a netbsd-5 and -current domU. With
> the file on r1.41 it works fine, with r1.42 it panics.
> 
> Panic message is included below. This is totally reproducible for me,
> so just let me know if you need more info.

The system calls xennet_init() to mount root, however sc_rx_ring is
still not initialized, leading to the page fault.

FWIW, the ring is initialized thanks to the Xen device "InitWait" state.
I'll look into splitting initialization and "feature query" in two tomorrow.

-- 
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost