Re: [PATCH net-next v2 0/6] hv_netvsc: avoid races on mtu change/set channels

[David Miller]

From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Date: Fri, 13 May 2016 13:55:19 +0200

> Changes since v1:
> - Rebased to net-next [Haiyang Zhang]
> 
> Original description:
> 
> MTU change and set channels operations are implemented as netvsc device
> re-creation destroying internal structures (struct net_device stays). This
> is really unfortunate but there is no support from Hyper-V host to do it
> in a different way. Such re-creation is unsurprisingly racy, Haiyang
> reported a crash when netvsc_change_mtu() is racing with
> netvsc_link_change() but I was able to identify additional races upon
> investigation. Both netvsc_set_channels() and netvsc_change_mtu() race
> against:
> 1) netvsc_link_change()
> 2) netvsc_remove()
> 3) netvsc_send()
> 
> To solve these issues without introducing new locks some refactoring is
> required. We need to get rid of very complex link graph in all the
> internal structures and avoid traveling through structures which are being
> removed.

Series applied, thanks.