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

[Greg KH <gregkh@linuxfoundation.org>]

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?

thanks,

greg k-h