MFC VIMAGE fixes to 11-stable

[Kristof Provost]

On 20 Apr 2017, at 12:42, Marko Zec wrote:
> The real culprit lies somewhere in PF code which operates on a wrong
> vnet.  Without a backtrace it's difficult to guess, but a quick read
> reveals that
>
> pfi_initialize()
>
> is called from the default vnet context, and subsequently registers
> interface eventhandlers so that all interface attach, change and 
> detach
> events will be always executed in the default vnet, regardless of the
> real vnet where the interfaces bound to the events actually reside.  
> In
> other words,
>
> pfi_attach_group_event()
> pfi_change_group_event()
> pfi_detach_group_event()
>
> will operate fine only in the default vnet, but will wreak havoc
> otherwise.  Hence, those handlers should be fixed first.
>
I don’t think that’s right.

The event handler doesn’t carry vnet information.  It’s just called 
in whatever
vnet is active when it’s invoked.
There's no CURVNET_SET() in the EVENTHANDLER_INVOKE() macro.

That means that we end up in pf_attach_group_event() with CURVNET set to 
the
relevant vnet, not to the default vnet.

There are certainly still issues with pf and vnets, but I don't think 
this is
one.

Regards,
Kristof