Thread (36 messages) 36 messages, 11 authors, 2011-08-22

Re: KVM induced panic on 2.6.38[2367] & 2.6.39

From: Bart De Schuymer <hidden>
Date: 2011-06-07 18:04:11
Also in: kvm, linux-mm, lkml, netfilter-devel

Possibly related (same subject, not in this thread)

Op 7/06/2011 16:40, Brad Campbell schreef:
On 07/06/11 21:30, Patrick McHardy wrote:
quoted
On 07.06.2011 05:33, Brad Campbell wrote:
quoted
On 07/06/11 04:10, Bart De Schuymer wrote:
quoted
Hi Brad,

This has probably nothing to do with ebtables, so please rmmod in case
it's loaded.
A few questions I didn't directly see an answer to in the threads I
scanned...
I'm assuming you actually use the bridging firewall functionality. So,
what iptables modules do you use? Can you reduce your iptables 
rules to
a core that triggers the bug?
Or does it get triggered even with an empty set of firewall rules?
Are you using a stock .35 kernel or is it patched?
Is this something I can trigger on a poor guy's laptop or does it
require specialized hardware (I'm catching up on qemu/kvm...)?
Not specialised hardware as such, I've just not been able to reproduce
it outside of this specific operating scenario.
The last similar problem we've had was related to the 32/64 bit compat
code. Are you running 32 bit userspace on a 64 bit kernel?
No, 32 bit Guest OS, but a completely 64 bit userspace on a 64 bit 
kernel.

Userspace is current Debian Stable. Kernel is Vanilla and qemu-kvm is 
current git
If the bug is easily triggered with your guest os, then you could try to 
capture the traffic with wireshark (or something else) in a 
configuration that doesn't crash your system. Save the traffic in a pcap 
file. Then you can see if resending that traffic in the vulnerable 
configuration triggers the bug (I don't know if something in Windows 
exists, but tcpreplay should work for Linux). Once you have such a 
capture , chances are the bug is even easily reproducible by us (unless 
it's hardware-specific). Success isn't guaranteed, but I think it's 
worth a shot...

cheers,
Bart


-- 
Bart De Schuymer
www.artinalgorithms.be

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