From: Wei Liu <wei.liu2@citrix.com>
To: Nick Pegg <npegg@linode.com>
Cc: "ij@2013.bluespice.org" <ij@2013.bluespice.org>,
Ian Campbell <Ian.Campbell@citrix.com>,
"konrad.wilk@oracle.com" <konrad.wilk@oracle.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
"annie.li@oracle.com" <annie.li@oracle.com>,
Jan Beulich <JBeulich@suse.com>,
wei.liu2@citrix.com
Subject: Re: [PATCH] xen-netfront: drop skb when skb->len > 65535
Date: Wed, 6 Mar 2013 17:31:59 +0000 [thread overview]
Message-ID: <1362591119.29093.12.camel@zion.uk.xensource.com> (raw)
In-Reply-To: <51377AD9.80304@linode.com>
On Wed, 2013-03-06 at 17:20 +0000, Nick Pegg wrote:
> On 3/2/13 8:32 AM, Wei Liu wrote:
> >
> > As Nick (npegg@linode.com) pointed out in his email, he saw size 65538.
> > I can reproduce this as well by setting vif's mtu to 100 then run iperf.
> > 100 was just a random number I came up with when I played with
> > fragmentation.
> >
>
> Wei: How exactly did you set the MTU on the vif and what were your
> arguments to iperf? I tried this on a test host and was unable to
> trigger the XSA-39 protection.
>
Sorry I didn't state this clearly. I tend to call the interface inside
VM as vif as well. I did this inside a VM, ifconfig eth0 mtu 100.
Nothing fancy added to iperf command line, just `iperf -c XXX` in VM and
`iperf -s` in host (I limited the test time with -t though).
> As for a more graceful punishment, I noticed that xenvif_carrier_off()
> uses netif_carrier_off() to discard queued packets. Would doing a
> netif_carrier_off() and then a netif_carrier_on() be sufficient to drop
> the bad packets and keep netback from spinning? Would blinking the vif's
> carrier in this way allow the DomU to gracefully resume network traffic?
>
I think the spinning has something to do with the ring, not packets --
I'm not very sure though, because I didn't take part in the discussion /
development of XSA-39. Draining host queues is not likely to fix this.
Wei.
>
> -Nick
next prev parent reply other threads:[~2013-03-06 17:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-01 16:31 [PATCH] xen-netfront: drop skb when skb->len > 65535 Wei Liu
2013-03-01 16:34 ` Wei Liu
2013-03-01 16:48 ` Jan Beulich
2013-03-01 17:00 ` Wei Liu
2013-03-02 2:54 ` Ian Campbell
2013-03-02 13:32 ` Wei Liu
2013-03-03 5:02 ` annie li
2013-03-06 17:20 ` Nick Pegg
2013-03-06 17:31 ` Wei Liu [this message]
2013-03-06 17:57 ` Jacek Milewicz
2013-03-06 18:04 ` Wei Liu
2013-03-03 4:13 ` annie li
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=1362591119.29093.12.camel@zion.uk.xensource.com \
--to=wei.liu2@citrix.com \
--cc=Ian.Campbell@citrix.com \
--cc=JBeulich@suse.com \
--cc=annie.li@oracle.com \
--cc=ij@2013.bluespice.org \
--cc=konrad.wilk@oracle.com \
--cc=npegg@linode.com \
--cc=xen-devel@lists.xen.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.