From mboxrd@z Thu Jan 1 00:00:00 1970 From: Casey Schaufler Subject: Re: Network hang after c3f1010b30f7fc611139cfb702a8685741aa6827 with CIPSO & Smack Date: Wed, 6 Jul 2016 11:01:44 -0700 Message-ID: <6d1249a6-6176-414e-0df8-d7df8dac1cbd@schaufler-ca.com> References: <7d833f59-c68f-f779-4de4-15bc0b26ac7c@cumulusnetworks.com> <66709b13-15a7-8d03-9e84-e4be9aab60b5@schaufler-ca.com> <9998a0da-b273-43d4-84ad-a0539e6a69ac@cumulusnetworks.com> <5de95a23-fd64-d911-d4b0-88de51ab12a4@schaufler-ca.com> <9cb32128-176b-85cf-8ea8-465704f667e7@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Linux-Netdev To: David Ahern , David Miller , Paul Moore Return-path: Received: from nm31-vm6.bullet.mail.bf1.yahoo.com ([72.30.239.14]:57475 "EHLO nm31-vm6.bullet.mail.bf1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754168AbcGFSIs (ORCPT ); Wed, 6 Jul 2016 14:08:48 -0400 In-Reply-To: <9cb32128-176b-85cf-8ea8-465704f667e7@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 7/6/2016 10:40 AM, David Ahern wrote: > On 7/6/16 10:24 AM, Casey Schaufler wrote: >> On 7/6/2016 9:28 AM, David Ahern wrote: >>> On 7/5/16 6:31 PM, Casey Schaufler wrote: >>>> On 7/5/2016 5:49 PM, David Ahern wrote: >>>>> On 7/5/16 5:38 PM, Casey Schaufler wrote: >>>>>> I have encountered a system hang with my Smack >>>>>> networking tests that bisects to the change below. >>>>>> I can't say that I have any idea why the change >>>>>> would impact the Smack processing, but there appears >>>>>> to be some serious packet processing going on. The >>>>>> Smack code is using CIPSO on the loopback interface. >>>>>> The test is supposed to verify that labels can be >>>>>> set on the packets using CIPSO. Unlabeled packets >>>>>> do not appear to be impacted. I do not know if SELinux >>>>>> is affected, and if not, why not. Smack and SELinux >>>>>> use CIPSO differently. >>>>> >>>>> What are the commands to repeat the test? >>>>> >>>> There is a tar file attached with the tests. >>>> Put the etc/smack/user file into /etc/smack/user. >>>> In the tools-2012 directory run make to build >>>> the tools. The test in question is called >>>> testnetworking.sh and needs to be run as root. >>>> You will need to configure Smack in the kernel, >>>> of course. >>>> >>> >>> I understand Paul's point and glad to see the changes are not causing issues with his SELinux testing. >>> >>> I have tried to reproduce the lockup you are seeing but not successful. I am using a jessie based VM with latest net-next kernel. >>> >>> root@kenny-jessie3:~/smack/tools-2012# zcat /proc/config.gz | grep SMACK >>> CONFIG_SECURITY_SMACK=y >>> CONFIG_SECURITY_SMACK_BRINGUP=y >>> CONFIG_SECURITY_SMACK_NETFILTER=y >>> # CONFIG_DEFAULT_SECURITY_SMACK is not set >> >> CONFIG_DEFAULT_SECURITY_SMACK needs to be set. > > ok. That caused more interesting output but still no hang after all of the snap-crackle-and-pops. > I find the test occasionally passes without hanging, but will hang the system if repeated. I am running on Ubuntu and Fedora, both with systemd, which may be a contributing factor. I run under qemu, and am based on Linus' tree.