Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:51012 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754587Ab2ITMkZ (ORCPT ); Thu, 20 Sep 2012 08:40:25 -0400 Received: by pbbrr4 with SMTP id rr4so121231pbb.19 for ; Thu, 20 Sep 2012 05:40:24 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1348144524.4161.26.camel@jlt4.sipsolutions.net> References: <1347361823.26457.3.camel@sauron.fi.intel.com> <1DC40B07CD6EC041A66726C271A73AE6195AE9C8@IRSMSX102.ger.corp.intel.com> <1347631355.5263.19.camel@sauron.fi.intel.com> <1347640763.5263.24.camel@sauron.fi.intel.com> <1347892887.7112.9.camel@sauron.fi.intel.com> <1348142775.2388.10.camel@sauron.fi.intel.com> <1348144524.4161.26.camel@jlt4.sipsolutions.net> Date: Thu, 20 Sep 2012 14:40:24 +0200 Message-ID: (sfid-20120920_144028_758401_14E0E501) Subject: Re: regression: tethering fails in 3.5 with iwlwifi From: Eric Dumazet To: Johannes Berg Cc: artem.bityutskiy@linux.intel.com, linux-wireless@vger.kernel.org, netdev Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: OK, but which netif_receive_skb(), as I count 5 occurrences in net/mac80211/rx.c ? Instead of skb_linearize() calls you could try several values of XXX in pskb_may_pull(skb, XXX) So that you make sure XXX bytes are available in skb->head, and not the whole frame. One you know the limit for XXX, it might give a clue where a pskb_may_pull(skb, XXX) is missing. On Thu, Sep 20, 2012 at 2:35 PM, Johannes Berg wrote: > Hi, > >> > 56138f5 iwlwifi: dont pull too much payload in skb head >> > 3edaf3e mac80211: manage AP netdev carrier state >> >> The second patch (AP carrier state) actually exposed a connman issue >> which I fixed and submitted a connman patch: >> http://lists.connman.net/pipermail/connman/2012-September/011232.html >> >> However, Eric's patch still causes tethering problems to me. > > > Let me recap a bit. Artem is using connman, which sets up the wifi > interface as part of a bridge. It runs wpa_supplicant to create an AP > (only AP and mesh mode interfaces can be bridged anyway). > > > Eric, you said: > >> I would say some part of the stack assumes a header (I dont know wich >> one ?) is pulled in skb->head/data, and thats a bug. >> >> Always use pskb_may_pull(skb, XXX) to make sure you can access XXX >> bytes in skb->data > > I thought we'd figure out which part of the stack assumes a header, so I > asked Artem to test a one-line patch which adds "skb_linearize()" before > "netif_receive_skb()" in mac80211. This makes it work, but I'm not sure > where after that the bad assumption might be. > > johannes >