yet another ssh hanging issue.

Rachit Siamwalla rachit at
Tue Jun 12 11:19:32 EST 2001

This problem does not fit into the normal sleep 20 &; exit hanging problem. 

Basically, we use ssh as a secure RPC mechanism to install / update RPMs
remotely. The problem is ssh "hangs" after installing an RPM "sometimes".
And, no, that RPM does not start any daemons or hold onto any fds / ttys.

Attached is various lsof / strace / ps / etc. information on the server
after the "hanging" took place. We didn't attach the same for the client,
although we did look, and the client seemed to be selecting on the "normal"
fds, and waiting for the server to exit. (it was an ssh myhost rpm -U
command) We couldn't get -v / -d output because this problem happens
relatively rarely. No zombie processes.

One thing that confuses us is fd #5. It is a unix socket but doesn't seem to
look like a connection to /dev/log. ssh doesn't seem to connect to any other
unix socket except for /dev/log, but then releases the connection rightaway.

We will attempt to reproduce it and narrow down the possible reasons and
hopefully eventually get -v / -d output, but hope this email helps. Also if
someone knows whether anything significant changed in 2.9 that would likely
fix these issues, that would be cool. Otherwise I'd like to postpone
upgrading to 2.9, because it is an extreme pain to upgrade everyone's
machine to 2.9 remotely, especially if i'm not sure if thats going to fix it
(I'll never know until weeks afterward).

Let me know if there are any questions. And thank you *very* much for a
great package. It is making my job so much easier.


Environment info.

Client: generic openssh 2.5.2p2 compiled without patches and statically
linked to OpenSSL. Linux i386
Server: redhat 7.1 default openssh 2.5.2p2-5. Linux i386

Only configuration changes on server:

Protocol 2 (only)
BatchMode yes
Port 19635 (some random other port)



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