Fw: [Bug 12327] New: Intermittent TCP issues with => 2.6.27

Fw: [Bug 12327] New: Intermittent TCP issues with => 2.6.27

[Stephen Hemminger]

Begin forwarded message:

Date: Mon, 29 Dec 2008 18:52:40 -0800 (PST)
From: bugme-daemon@bugzilla.kernel.org
To: shemminger@linux-foundation.org
Subject: [Bug 12327] New: Intermittent TCP issues with => 2.6.27


http://bugzilla.kernel.org/show_bug.cgi?id=12327

           Summary: Intermittent TCP issues with => 2.6.27
           Product: Networking
           Version: 2.5
     KernelVersion: 2.6.27
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: IPV4
        AssignedTo: shemminger@linux-foundation.org
        ReportedBy: speedster@haveacry.com


Latest working kernel version: 2.6.26.8
Earliest failing kernel version: 2.6.27
Distribution: Ubuntu
Hardware Environment: amd64, KVM
Software Environment:
Problem Description:

As reported in LP #296767
(https://bugs.launchpad.net/ubuntu/+source/linux/+bug/296767) I am experiencing
intermittent TCP issues over a PPP ADSL2+ connection with the only change being
an upgrade to 2.6.27.

A number of websites, ping, traceroute work correctly but I simply can't
connect to several including:

- store.apple.com
- youtube.com
- ANZ internet banking (anz.com.au)
- MSN messenger

I have also tried compiling a generic 2.6.28-rc4 kernel and this still suffers
from the same issue, however if I reboot into the previous Ubuntu kernel
(2.6.24) or a vanilla 2.6.26 kernel the issue disappears.

Steps to reproduce:

1. Use a KVM guest as a gateway to a PPP internet connection
2. Boot with kernel <= 2.6.26
3. Observe functioning networking
4. Boot into 2.6.27+
5. Observe broken networking


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Re: Fw: [Bug 12327] New: Intermittent TCP issues with => 2.6.27

[Herbert Xu]

Stephen Hemminger <shemminger@linux-foundation.org> wrote:
> 
> A number of websites, ping, traceroute work correctly but I simply can't
> connect to several including:
> 
> - store.apple.com
> - youtube.com
> - ANZ internet banking (anz.com.au)
> - MSN messenger

I failed to reproduce this on 2.6.28-rc9.  I even used the same
IP address as shown in your pcap file, 17.149.156.10.

In fact, your pcap file shows that the two kernels produce almost
exactly the same content in the TCP headers.  The only material
difference was the window size, which differed by 32 bytes.

So I'd suggest you take a look at other nodes on the path between
you and those websites, or try turning things such as window
scaling off.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: Fw: [Bug 12327] New: Intermittent TCP issues with => 2.6.27

[Ilpo Järvinen]

On Fri, 2 Jan 2009, Herbert Xu wrote:

> Stephen Hemminger <shemminger@linux-foundation.org> wrote:
> > 
> > A number of websites, ping, traceroute work correctly but I simply can't
> > connect to several including:
> > 
> > - store.apple.com
> > - youtube.com
> > - ANZ internet banking (anz.com.au)
> > - MSN messenger
> 
> I failed to reproduce this on 2.6.28-rc9.  I even used the same
> IP address as shown in your pcap file, 17.149.156.10.

Same for me, though I don't have ppp in the setup like he does
(see the mail in the other thread).

> In fact, your pcap file shows that the two kernels produce almost
> exactly the same content in the TCP headers. The only material
> difference was the window size, which differed by 32 bytes.

Yeah, nothing wrong with tcp/ip side.

> So I'd suggest you take a look at other nodes on the path between
> you and those websites, or try turning things such as window
> scaling off.

He did already turn things off without any success, the original report 
for ubuntu is at:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/296767

I doubt that the original reporter received this mail anyway... There's 
another thread (fwd by Andrew) which has more content already.

-- 
 i.