Re: Problems with looping/hanging sshd on AIX 4.3.3

From: Nicholas Dronen (
Date: 01/09/03

From: Nicholas Dronen <>
Date: 09 Jan 2003 05:38:16 GMT

In comp.unix.aix Patrick Van der Veken <> wrote:
> Hi all,

> I am trying to help a collegue to fix a problem he is encountering on 2 AIX
> systems (AIX 4.3.3, patchlevel 10). OpenSSH v1.2.3 is installed. The
> following problem occurs on and off when using 'scp' to copy files back and
> forth from the servers: the sshd goes into a loop and starts eating 25%-50%
> of the CPU time. The sshd needs to be killed to fix the problem. Nothing
> particular shows up in the syslog.

Did he start the daemon with maximal debugging?

> My question is: has anyone seen such behaviour before? I have picked up some
> hints on PTY related issues on AIX. I realize that the OpenSSH version is
> old but for policy reasons we are unable to upgrade to a newer release and
> test it.

It is possible that this, as you suggest, is a bug in AIX, related
to ttys, sockets, or anything else. If you can't get any critical
output using debugging flags, I'd suggest getting the source code
for that version of ssh, possibly recompiling, and definitely either

        * kill -SEGV it when it starts to loop, and look at the
        core file later; or
        * run it under the debugger and ^C when it starts to loop.



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