Re: Request for stable 4.14.x inclusion: net: don't call update_pmtu unconditionally

[David Miller <davem@davemloft.net>]

From: Greg KH <gregkh@linuxfoundation.org>
Date: Fri, 27 Apr 2018 15:51:25 +0200

> On Fri, Apr 27, 2018 at 02:20:07PM +0200, Thomas Deutschmann wrote:
>> On 2018-04-22 23:50, Thomas Deutschmann wrote:
>> > Hi,
>> > 
>> > please add
>> > 
>> >> From f15ca723c1ebe6c1a06bc95fda6b62cd87b44559 Mon Sep 17 00:00:00 2001
>> >> From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
>> >> Date: Thu, 25 Jan 2018 19:03:03 +0100
>> >> Subject: net: don't call update_pmtu unconditionally
>> >>
>> >> Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
>> >> "BUG: unable to handle kernel NULL pointer dereference at           (null)"
>> >>
>> >> Let's add a helper to check if update_pmtu is available before calling it.
>> >>
>> >> Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
>> >> Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
>> >> CC: Roman Kapl <code@rkapl.cz>
>> >> CC: Xin Long <lucien.xin@gmail.com>
>> >> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
>> >> Signed-off-by: David S. Miller <davem@davemloft.net>
>> > 
>> > to 4.14.x.
>> > 
>> > This fixes NULL derefs caused by a93bf0ff4490 ("vxlan: update
>> > skb dst pmtu on tx path"), which was backported to 4.14.24.
>> 
>> *ping* - Not yet applied and not yet queued. Is there a problem with the
>> patch which prevents a cherry-pick for 4.14.x?
> 
> This looks like an "obvious" fix for me to pick up.
> 
> Dave, any objections for me just grabbing it as-is?

No objections, thanks everyone.