From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Justin P. Mattock" Subject: Re: BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0 Date: Wed, 23 Jun 2010 14:44:58 -0700 Message-ID: <4C22805A.3080307@gmail.com> References: <20100623141622.GC15205@tuxdriver.com> <4C223DCA.5090704@gmail.com> <1277314167.2469.1144.camel@edumazet-laptop> <4C224E06.40806@iki.fi> <4C22508A.8060002@gmail.com> <4C226FCA.2030604@iki.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Eric Dumazet , "John W.Linville" , netdev@vger.kernel.org, Linux Kernel Mailing List , davem@davemloft.net To: =?UTF-8?B?VGltbyBUZXLDpHM=?= Return-path: In-Reply-To: <4C226FCA.2030604@iki.fi> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 06/23/2010 01:34 PM, Timo Ter=C3=A4s wrote: > On 06/23/2010 09:20 PM, Justin P. Mattock wrote: >> On 06/23/10 11:10, Timo Ter=C3=A4s wrote: >>> On 06/23/2010 08:29 PM, Eric Dumazet wrote: >>> >>>> Le mercredi 23 juin 2010 =C3=A0 10:00 -0700, Justin P. Mattock a =C3= =A9crit : >>>> >>>>> o.k. the bisect is pointing to the below results.. >>>>> (I tried git revert xxx but this commit is too big >>>>> so I'll(hopefully)manually revert it on the latest HEAD to >>>>> see if this is the actual problem im experiencing) >>>>> >>>>> 80c802f3073e84c956846e921e8a0b02dfa3755f is the first bad commit >>>>> commit 80c802f3073e84c956846e921e8a0b02dfa3755f >>>>> Author: Timo Ter=C3=83=C2=A4s >>>>> Date: Wed Apr 7 00:30:05 2010 +0000 >>>>> >>>>> xfrm: cache bundles instead of policies for outgoing flows >>>>> >>>>> __xfrm_lookup() is called for each packet transmitted out = of >>>>> system. The xfrm_find_bundle() does a linear search which = can >>>>> kill system performance depending on how many bundles are >>>>> required per policy. >>>>> >>>>> This modifies __xfrm_lookup() to store bundles directly in >>>>> the flow cache. If we did not get a hit, we just create a = new >>>>> bundle instead of doing slow search. This means that we ca= n now >>>>> get multiple xfrm_dst's for same flow (on per-cpu basis). >>>>> >>>>> Signed-off-by: Timo Teras >>>>> Signed-off-by: David S. Miller >>>>> >>>>> :040000 040000 d8e60f5fa4c1329f450d9c7cdf98b34e6a177f22 >>>>> 9f576e68e5bf4ce357d7f0305aee5f410250dfe2 M include >>>>> :040000 040000 f2876df688ee36907af7b4123eea96592faaed3e >>>>> a3f6f6f94f0309106856cd99b38ec90b024eb016 M net >>>>> >>>> Thanks a lot for bisecting Jutin, this is really appreciated. >>>> >>>> crash is in xfrm_bundle_ok() >>>> >>>> if (xdst->policy_genid !=3D atomic_read(&xdst->pols[0]->genid)) >>>> return 0; >>>> >>>> xdst->pols[0] contains a NULL pointer >>>> >>> That does not really make sense, if we get this far; there's a vali= d >>> xfrm_state with the bundle. This means that there existed a policy = with >>> it too. >>> >>> I'll take a deeper look at this tomorrow. Would it be possible to s= ee >>> your xfrm policies? >>> >>> - Timo >>> >>> >> >> @Eric sure no problem doing the bisect... >> >> as for the xfrm policy here is the link that I used to setup ipsec: >> http://www.linuxfromscratch.org/hints/downloads/files/ipsec.txt >> (just change the keys if doing real world work..(but for me just tes= ting). >> >> below is a temporary fix for me to get this working, tcpdump reports >> everything is doing what it should be >> 11:16:32.496166 IP xxxxx> xxxxx: AH(spi=3D0x00000200,seq=3D0x1090): >> ESP(spi=3D0x00000201,seq=3D0x1090), length 56 >> 11:16:32.496212 IP xxxxx> xxxxx: AH(spi=3D0x00000200,seq=3D0x1091): >> ESP(spi=3D0x00000201,seq=3D0x1091), length 56 >> 11:16:32.496259 IP xxxxx> xxxxx: AH(spi=3D0x00000200,seq=3D0x1092): >> ESP(spi=3D0x00000201,seq=3D0x1092), length 56 >> >> (tested a few mins ago, but not the right fix..) > > Yes, that would break some other obscure scenarios. > > Looks like it's ah inside esp. So you get chain of bundles. And only = the > first bundle gets a policy. Should have thought of that. Does the bel= ow > fix it for you? > > diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c > index 4bf27d9..af1c173 100644 > --- a/net/xfrm/xfrm_policy.c > +++ b/net/xfrm/xfrm_policy.c > @@ -2300,7 +2300,8 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, str= uct > xfrm_dst *first, > return 0; > if (xdst->xfrm_genid !=3D dst->xfrm->genid) > return 0; > - if (xdst->policy_genid !=3D atomic_read(&xdst->pols[0]->genid)) > + if (xdst->num_pols> 0&& > + xdst->policy_genid !=3D atomic_read(&xdst->pols[0]->genid)) > return 0; > > if (strict&& fl&& > > yeah this works.. I can see AH and ESP showing up with tcpdump.. looks good.. Reported-Bisected-By: Justin P. Mattock cheers, Justin P. Mattock