From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Beth Kon <eak@us.ibm.com>, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] accidental mistyping of command line kills networking
Date: Wed, 28 Oct 2009 08:29:42 +0200 [thread overview]
Message-ID: <4AE7E4D6.1000008@redhat.com> (raw)
In-Reply-To: <4AE769A3.9080205@codemonkey.ws>
On 10/27/2009 11:44 PM, Anthony Liguori wrote:
>
> It's actually not okay. You're creating a bridge with two tap devices
> on the bridge that happen to be connected in qemu by a vlan. If one
> tap device receives a packet, qemu is going to forward that packet to
> the other tap device, which will in turn send the packet to the bridge
> which in turn sends it to the first tap device.
>
> Resulting in an infinite networking loop.
>
It shouldn't kill networking though. If a guest has two nics connected
to the same host bridge (a reasonable configuration), and then connects
these two nics through its own bridge, it creates the same sort of
loop. If that kills networking, we have a guest-initiated DoS (not that
the userspace-initiated DoS was much better).
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2009-10-28 6:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-27 19:12 [Qemu-devel] accidental mistyping of command line kills networking Beth Kon
2009-10-27 21:10 ` Beth Kon
2009-10-27 21:44 ` Anthony Liguori
2009-10-28 6:29 ` Avi Kivity [this message]
2009-10-28 8:34 ` Gleb Natapov
2009-10-28 8:55 ` Avi Kivity
2009-10-28 9:07 ` Gleb Natapov
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