Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932906AbbELQeH (ORCPT ); Tue, 12 May 2015 12:34:07 -0400 Received: from mail-qk0-f174.google.com ([209.85.220.174]:34662 "EHLO mail-qk0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753051AbbELQeD (ORCPT ); Tue, 12 May 2015 12:34:03 -0400 Message-ID: <55522B78.3090908@gmail.com> Date: Tue, 12 May 2015 12:34:00 -0400 From: Vlad Yasevich User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Eric Dumazet , Wolfgang Walter CC: Cong Wang , LKML , Hannes Frederic Sowa , Linux Kernel Network Developers Subject: Re: kernel >= 4.0: crashes when using traceroute6 with isatap References: <1770409.aMESoOv08f@h2o.as.studentenwerk.mhn.de> <1430939400.14545.65.camel@edumazet-glaptop2.roam.corp.google.com> <2723870.nq54KKjWkm@h2o.as.studentenwerk.mhn.de> <1430952158.14545.97.camel@edumazet-glaptop2.roam.corp.google.com> In-Reply-To: <1430952158.14545.97.camel@edumazet-glaptop2.roam.corp.google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2059 Lines: 65 On 05/06/2015 06:42 PM, Eric Dumazet wrote: > On Thu, 2015-05-07 at 00:04 +0200, Wolfgang Walter wrote: >> Am Mittwoch, 6. Mai 2015, 12:10:00 schrieb Eric Dumazet: >>> On Wed, 2015-05-06 at 11:15 -0700, Cong Wang wrote: >>>> (Cc'ing netdev.) >>>> >>>> On Sat, May 2, 2015 at 5:29 AM, Wolfgang Walter wrote: >>>>> Am Samstag, 2. Mai 2015, 02:16:36 schrieb Wolfgang Walter: >>>>>> Hello, >>>>>> >>>>>> kernel 4.0 (and 4.0.1) crashes immediately when I use traceroute6 with >>>>>> an >>>>>> isatap-tunnel. >>>>> >>>>> I did some further tests. To trigger the crash you need >>>>> >>>>> * isatap-tunnel (probably any sit-tunnel will do it) >>>>> * raw-socket >>>>> * udp >>>>> >>>>> Using icmpv6 or tcp i.e. does not trigger it. >>>> >>>> Do you have a script to reproduce it? >>>> >>>> >>>> Thanks for the bug report! >>>> -- >>> >>> Please Wolfgang try to revert 32dce968dd987adfb0c00946d78dad9154f64759 >>> ("ipv6: Allow for partial checksums on non-ufo packets") >> >> Indeed, that fixes the problem. > > Yes, setting skb->csum to 0 is clearly wrong for CHECKSUM_PARTIAL > > Would you try : > > diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c > index 7fde1f265c90e90f16291e6c861b6e242111c25b..694ae630e1ca67e25ab1e5f6dd0b3597db3669b0 100644 > --- a/net/ipv6/ip6_output.c > +++ b/net/ipv6/ip6_output.c > @@ -1416,6 +1416,10 @@ alloc_new_skb: > data += fragheaderlen; > skb->transport_header = (skb->network_header + > fragheaderlen); > + if (csummode == CHECKSUM_PARTIAL) { > + skb->csum_start = skb_transport_header(skb) - skb->head; > + skb->csum_offset = offsetof(struct udphdr, check); > + } > if (fraggap) { > skb->csum = skb_copy_and_csum_bits( > skb_prev, maxfraglen, > > > So why is this not an issue in __ip_append_data()? -vlad -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/