linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Alexander Aring <aar@pengutronix.de>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Palma <david.palma@ntnu.no>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	stefan@osg.samsung.com, linux-wpan@vger.kernel.org
Subject: Re: skb_over_panic using UDP and 6lowpan / fakelb
Date: Mon, 17 Apr 2017 15:25:48 +0200	[thread overview]
Message-ID: <0ddbdbde-8610-0ea5-bae2-4ec2702927dc@pengutronix.de> (raw)
In-Reply-To: <CAM_iQpWqQj3FLpBLE1Z+==Z7tJGXHyHXTvLmKRCNjyc=vtQvnQ@mail.gmail.com>


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 <david.palma@ntnu.no> 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

      reply	other threads:[~2017-04-17 13:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-27  9:16 skb_over_panic using UDP and 6lowpan / fakelb David Palma
2017-04-03 17:29 ` Cong Wang
2017-04-17 13:25   ` Alexander Aring [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=0ddbdbde-8610-0ea5-bae2-4ec2702927dc@pengutronix.de \
    --to=aar@pengutronix.de \
    --cc=david.palma@ntnu.no \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wpan@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=stefan@osg.samsung.com \
    --cc=xiyou.wangcong@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).