[ovs-dev] [PATCH 1/2] datapath: backport: OVS: Ignore negative headroom value

[pravin shelar]

On Sat, Aug 13, 2016 at 10:08 AM, Jesse Gross <jesse at kernel.org> wrote:
> On Fri, Aug 12, 2016 at 10:49 AM, Pravin B Shelar <pshelar at ovn.org> wrote:
>> Upstream commit:
>>     commit 5ef9f289c4e698054e5687edb54f0da3cdc9173a
>>     Author: Ian Wienand <iwienand at redhat.com>
>>     Date:   Wed Aug 3 15:44:57 2016 +1000
>>
>>     OVS: Ignore negative headroom value
>>
>>     net_device->ndo_set_rx_headroom (introduced in
>>     871b642adebe300be2e50aa5f65a418510f636ec) says
>>
>>       "Setting a negtaive value reset the rx headroom
>>        to the default value".
>>
>>     It seems that the OVS implementation in
>>     3a927bc7cf9d0fbe8f4a8189dd5f8440228f64e7 overlooked this and sets
>>     dev->needed_headroom unconditionally.
>>
>>     This doesn't have an immediate effect, but can mess up later
>>     LL_RESERVED_SPACE calculations, such as done in
>>     net/ipv6/mcast.c:mld_newpack.  For reference, this issue was found
>>     from a skb_panic raised there after the length calculations had given
>>     the wrong result.
>>
>>     Note the other current users of this interface
>>     (drivers/net/tun.c:tun_set_headroom and
>>     drivers/net/veth.c:veth_set_rx_headroom) are both checking this
>>     correctly thus need no modification.
>>
>>     Thanks to Ben for some pointers from the crash dumps!
>>
>>     Cc: Benjamin Poirier <bpoirier at suse.com>
>>     Cc: Paolo Abeni <pabeni at redhat.com>
>>     Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1361414
>>     Signed-off-by: Ian Wienand <iwienand at redhat.com>
>>     Signed-off-by: David S. Miller <davem at davemloft.net>
>>
>> Signed-off-by: Pravin B Shelar <pshelar at ovn.org>
>
> Acked-by: Jesse Gross <jesse at kernel.org>

Thanks. I pushed it to master.