Re: [PATCH net RFC] xen-netback: Fix grant ref resolution in RX path

[Zoltan Kiss <zoltan.kiss@citrix.com>]

On 14/05/14 17:40, Ian Campbell wrote:
>
> On Wed, 2014-05-14 at 14:25 +0100, Zoltan Kiss wrote:
>
>> But of course it should be carefully checked that functions which place
>> frags into another frags arrays should call orphan_frags, e.g. I guess
>> skb_shift does such thing. That's what I intend to start another thread
>> about.
>
> I see Eric has posted a fix for skb_try_coalesce(), but is that likely
> to be acceptable for 3.15? How many other similar patches are we
> expecting and/or how long do you think this careful checking will take?
>
> Given that we are now at 3.15-rc5 I think we need to decide how to
> proceed, either push ahead fixing all these issues or (partially) revert
> this netback feature and try again for 3.16.
I guess these problems apply to KVM as well, and it haven't caused them 
problem so far, so I guess the problem shouldn't be that big. I assume 
they are using this feature to send fragmented skbs out from a guest, 
but I might be wrong.
Anyway, I think I'll check tomorrow if there are further places to worry 
about, but I don't think if there are any of them which are easily 
reproducible.

Zoli