Re: [PATCH] Update pptp handling to avoid null pointer deref.

[David Miller]

From: Ian Kumlien <ian.kumlien@xxxxxxxxx>
Date: Mon,  2 Jan 2017 00:19:36 +0100

> __skb_flow_dissect can be called with a skb or a data packet, either
> can be NULL. All calls seems to have been moved to __skb_header_pointer
> except the pptp handling which is still calling skb_header_pointer.
> 
> skb_header_pointer will use skb->data and thus:
 ...
> ---
> 
> Signed-off-by: Ian Kumlien <ian.kumlien@xxxxxxxxx>

You need to fix some parts of your submission.

Do not put the signoff after the "---", git will remove all text
after that "---" from the commit message.

You must include a proper "Fixes: " tag which indicates which change
introduced this regression.  This is critical for analyzing your fix
and also for figuring out which -stable releases your fix should be
backported to.

In this case the guilty commit is ab10dccb1160 ("rps: Inspect PPTP
encapsulated by GRE to get flow hash")