Re: [Bugme-new] [Bug 10903] New: ssh connections hang with 2.6.26-rc5

On Tue, 17 Jun 2008, Didier Raboud wrote:

Le lundi 16 juin 2008 15:21:25 Ilpo J�rvinen, vous avez �crit�:

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http://bugzilla.kernel.org/show_bug.cgi?id=10903

           Summary: ssh connections hang with 2.6.26-rc5
           Product: Networking
           Version: 2.5
     KernelVersion: 2.6.26-rc5
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: acme@ghostprotocols.net
        ReportedBy: didier@raboud.com


Latest working kernel version: 2.6.25-2
Earliest failing kernel version: 2.6.26-rc5
Distribution: Debian (Lenny + Sid)
Hardware Environment: amd64 (Dell Latitude D630)
Software Environment: KDE
Problem Description:

With kernel version 2.6.26-rc5, the ssh connections to remote
servers randomly
hang (no error message). No amelioration despite the activation of
"ServerAliveInterval" on both sides.

(...)

The common point is my use of "iwl3945" : I have always tried the ssh
connections through WiFi.

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So please gather this information (at least for the relevant
connections):

$ netstat -pn
$ cat /proc/net/tcp

I used a script which logged both every 15 seconds on both sides (in "screen" 
on server side). I then triggered a hang with several "seq 1 100" in the ssh 
session. The logs are in the attached debug_ssh_hang.tar.gz . The hang 
appeared between 234327 and 234342 on the client side (so somewhere between 
234324, 234339 and 234354 on the server side).

I hope it'll help.

Thanks, a quick look didn't indicate anything similar to one other report 
from H�kon... I'd probably need a tcpdump.

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You probably run it under X, no? Please switch beforehand to some other vt
(a textual one) then (Ctrl-Alt-Fn, where n < 6) and then log in and
running that command there and see if you get some output into screen
there. If you see something (e.g., a sudden OOPS message or some other
warning printed) when it locks up, the easiest things is to take a shot
with a digicam (or write it down somewhere else) and send that shot (or
those details) to us please.

I tried the following in vt1 (under the new 2.6.26-rc6 with kdm stopped):

# tcpdump -i wlan0 -w /tmp/tcpdump.wlan0

and I got the attached "soft lockup".

Thanks, I guess the folks at linux-wireless can continue in resolving this 
one with you (I'm out of time anyway now).

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...Once you have a tcpdump, I can probably figure at least something out
(though it might still just point to the right direction rather than
exposing the actual cause).

I can't get one... :)

...Ok.

-- 
 i.