Public bug reported:
I am filing this bug in the hope that it helps someone else with the
same problems.
Long description: I am running Ubuntu 10.10 Maverick Meercat 64bit. I
VPN in to work using Juniper Networks Network Connect ncsvc (like http
://mad-scientist.us/juniper.html, ncsvc version 6.5-0-Build15551). I
needed to install ia32-sun-java6-bin and ia32-libs to get the GUI to
work, and it worked well enough. This VPN uses IPSEC and a tun0 device
(may be important later).
Then I decided to investigate cloud computing and installed a bunch of
eucalyptus packages. After this, my VPN would consistently go dead
within a minute of connecting. I fiddled with the VPN client logging
and isolated a log entry consistently near the time of death which
seemed relevant:
ncsvc[p15519.t15519] adapter.warn Bad ip packet len 32 - should be 65535
(adapter.cpp:98)
Note the magic number 65535. This is an unreasonable packet length, and
seems like a buffer/pointer over/under-flow issue, or perhaps a
signed/unsigned issue which might arise when mixing 64bit and 32 bit
libraries.
I scoured the internet for clues but did not find anything that matched
well.
I totally un-installed Eucalyptus packages, rebooted and the problem
went away. Then, I one-by-one installed all the package dependencies
leading up to the eucalyptus-nc package, while also seeing which kernel
modules were loaded, until I got this problem to repeat. I eventually
isolated the problem down to the 'aoe' (ATA over Ethernet) module.
Now, if I have all the Eucalyptus packages intalled, I can use
lsmod/insmod/rmmod to load/unload the 'aoe' kernel module. If I have my
VPN running and pinging one of my work computers, and 'insmod' the 'aoe'
module, the VPN instantly locks up with the error message above.
This seems to me to be a problem with the 'aoe' module is injecting
something into the kernel networking stack which is causing some slight
network packet mis-aligning which the 32-bit Juniper Network Connect VPN
is very sensitive to.
Given the complexities of all the systems involved, I don't know where
to go next. Perhaps a more elegant and portable bug-test can be
developed. Someone very knowledgeable in linux kernel networking and
apps mixing 64/32-bit libs would probably have to think about this bug.
Even if this bug never gets fixed, I at least wanted to post my
observations out on the internet in hopes that other Juniper Network
Connect 32-bit ncsvc users (or developers) can save themselves several
days of troubleshooting and try un-loading the 'aoe' kernel module.
While researching my problems, I saw numerous other bugs related to the
'aoe' module where users described segfaults, kernel crashes and memory
allocation errors when pushing large quantities of network packets.
Perhaps there is a leak somewhere in the 'aoe' module code which is
creating many of these problems.
ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: upstart 0.6.6-3
ProcVersionSignature: Ubuntu 2.6.35-22.35-generic 2.6.35.4
Uname: Linux 2.6.35-22-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Thu Nov 18 23:42:21 2010
ExecutablePath: /sbin/init
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcEnviron: PATH=(custom, no user)
SourcePackage: upstart
** Affects: ubuntu
Importance: Undecided
Status: New
** Tags: amd64 apport-bug maverick
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Eucalpytus Cloud (aoe kernel module) crashes VPN tunnel (Juniper ncsvc)
https://bugs.launchpad.net/bugs/677343
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