Re: [PATCH v4 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Alexander Aring <alex.aring@gmail.com>]

On Tue, Sep 16, 2014 at 02:02:47PM +0200, Alexander Aring wrote:
> On Tue, Sep 16, 2014 at 01:53:57PM +0200, Alexander Aring wrote:
> > On Tue, Sep 16, 2014 at 01:47:59PM +0200, Alexander Aring wrote:
> > > On Tue, Sep 16, 2014 at 12:39:11PM +0100, Martin Townsend wrote:
> > > > Hi Alex,
> > > > On 16/09/14 12:36, Alexander Aring wrote:
> > > > > On Tue, Sep 16, 2014 at 12:01:59PM +0100, Martin Townsend wrote:
> > ...
> > > 
> > > and this also smells like side effects for me, because we have the
> > > local_skb which is sometimes freed inside of lowpan_process_data and
> > > returning skb. Then we don't know which we should kfree_skb now, the skb
> > > or local_skb now. Need to thing more about this to offer some solution,
> > > somebody agree here with me?
> > > 
> > 
> > I mean sometimes we do this *skb = *new and skb is the parameter and before we
> > did a consume_skb(skb); then local_skb is already freed after this and
> > returning an errno and we make kfree_skb(local_skb) will crash something,
> > I suppose.
> 
> I meant skb = new for the expand skb thing. And we can't never free
> kfree_skb(skb) here if (IS_ERR(skb) is true, but we can't decide if
> we need a kfree_skb(local_skb) or not, because we do a
> consume_skb($SKB_FROM_PARAMTER) in lowpan_process_data.
> 

This all comes now in, because the ERR_PTR conversion. So we have two
choices:

 - drop the ERR_PTR convertsion and make old behaviour
 - handle consume_skb/kfree_skb inside lowpan_process_data

- Alex