Return-Path: Date: Tue, 16 Sep 2014 14:18:44 +0200 From: Alexander Aring To: Martin Townsend Cc: Martin Townsend , linux-zigbee-devel@lists.sourceforge.net, linux-bluetooth@vger.kernel.org, linux-wpan@vger.kernel.org, marcel@holtmann.org, jukka.rissanen@linux.intel.com Subject: Re: [PATCH v4 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv Message-ID: <20140916121844.GA5349@omega> References: <1410865319-16310-1-git-send-email-martin.townsend@xsilon.com> <1410865319-16310-2-git-send-email-martin.townsend@xsilon.com> <20140916113614.GC4969@omega> <5418215F.5050308@xsilon.com> <20140916114759.GD4969@omega> <20140916115357.GE4969@omega> <20140916120247.GA5217@omega> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <20140916120247.GA5217@omega> List-ID: 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