Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753859AbdDQNZz (ORCPT ); Mon, 17 Apr 2017 09:25:55 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:54523 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753250AbdDQNZy (ORCPT ); Mon, 17 Apr 2017 09:25:54 -0400 Subject: Re: skb_over_panic using UDP and 6lowpan / fakelb To: Cong Wang References: <56012235-e1d0-1e5e-840a-cc8d5938c380@ntnu.no> Cc: David Palma , LKML , Linux Kernel Network Developers , stefan@osg.samsung.com, linux-wpan@vger.kernel.org From: Alexander Aring Message-ID: <0ddbdbde-8610-0ea5-bae2-4ec2702927dc@pengutronix.de> Date: Mon, 17 Apr 2017 15:25:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: aar@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1667 Lines: 49 Hi, sorry for the late reply. On 04/03/2017 07:29 PM, Cong Wang wrote: > (Cc'ing netdev and maintainers) > > On Mon, Mar 27, 2017 at 2:16 AM, David Palma wrote: >> >> Hi, >> >> Sending a simple UDP packet (39 bytes long), over a 6lowpan interface >> (using fakelb), creates a kernel panic (skb_over_panic). >> >> Steps to reproduce, and more details, can be found in: >> https://github.com/PalmaITEM/6lowpan-skb_over_panic >> >> This bug has been reported in >> https://bugzilla.kernel.org/show_bug.cgi?id=195059 >> >> I have found that lengths around 39 bytes can also trigger this >> behaviour and that longer packets are handled without problem. >> >> Verified in: >> >> - Linux version 4.9.0-0.bpo.2-amd64 (debian-kernel@lists.debian.org) >> (gcc version 4.9.2 (Debian 4.9.2-10) ) #1 SMP Debian 4.9.13-1~bpo8+1 >> (2017-02-27) >> - Linux version 4.10.4-1-ARCH (builduser@tobias) (gcc version 6.3.1 >> 20170306 (GCC) ) #1 SMP PREEMPT Sat Mar 18 19:39:18 CET 2017 >> >> >> I am not familiar with the process of reporting kernel bugs, so >> apologies beforehand. I am also available to provide any missing >> information. >> I will try to reproduce the failure with an x86_64 qemu virtual machine. Myself I use a 32 Bit qemu machine because I have a dependency on userspace software which use x86 assembler (somebody should change it to setjmp/longjmp)... it's the RIOT-OS native plattform. I use some cross compiling environment which doesn't support multilib yet, so I used always 32 Bit. btw: the github stuff is very useful and thanks for the hard work! I am on it to reproduce it. I will report when I have more information. - Alex