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Resent-date: Fri, 18 Mar 2005 15:07:34 -0800
Date: Fri, 18 Mar 2005 15:05:28 -0800
Resent-from: David Rothenberger <daveroth AT acm DOT org>
From: David Rothenberger <daveroth AT acm DOT org>
Subject: Re: ssh-add -l hanging with 20050316 snapshot
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On 3/17/2005 10:38 AM, David Rothenberger wrote:
> I've had keychain hang twice now while running "ssh-add -l". It happened 
> with an older snapshot and again this morning with a DLL I built from 
> CVS yesterday that corresponds to the 20050316 snapshot.

I've been able to reproduce this hang at will with the 20050316 
snapshot. I start an ssh-agent process, add a key to it, and then run 
"ssh-add -l" in a loop in two windows. This generally triggers the hang 
in a few minutes.

I've captured strace output from ssh-agent and the two ssh-add 
processes. The output is available here:

   http://mysite.verizon.net/res00a7j/ssh-agent.zip
   http://mysite.verizon.net/res00a7j/ssh-add.1.strace.txt
   http://mysite.verizon.net/res00a7j/ssh-add.1.strace.old.txt
   http://mysite.verizon.net/res00a7j/ssh-add.2.strace.txt
   http://mysite.verizon.net/res00a7j/ssh-add.2.strace.old.txt

The ssh-agent strace out is compressed because it's 2.4MB uncompressed. 
The uncompressed version is here if you're brave:

   http://mysite.verizon.net/res00a7j/ssh-agent.strace.txt

The strace's from the two ssh-add processes that hung are 
ssh-add.1.strace.txt and ssh-add.2.strace.txt. The "*.old.txt" traces 
are from the previous successful invocation of ssh-add in the two loops.

I used this simple script to capture the ssh-add traces:

#!/bin/bash
num=$1
while true; do
   [ -f /c/temp/ssh-add.$num.strace ] && \
     mv /c/temp/ssh-add.$num.strace /c/temp/ssh-add.$num.strace.2
   date
   strace -o /c/temp/ssh-add.$num.strace ssh-add -l
done

I ran it in two windows as "./ssh-add-loop.sh 1" and "./ssh-add-loop.sh 2".

Two things caught my eye when looking at the traces. In 
ssh-add.2.strace.txt, I saw this:

   252  122112 [main] ssh-add 4120 fhandler_socket::signal_secret_event: signaled secret_event
   121  122233 [main] ssh-add 4120 fhandler_socket::eid_pipe_name: \\.\pipe\cygwin-unix-/tmp/ssh-wxIlND2024/agent.2024
  2556  124789 [main] ssh-add 4120 fhandler_socket::connect: Receiving eid credentials failed: Win32 error 231

although the eid credentials were received successfully by ssh-add.1.

Also, at the end of the traces for the two hung ssh-add processes and 
ssh-agent, I saw this.

7963651 8097324 [sig] ssh-add 4120 pinfo::init: execed process windows pid 4884, cygwin pid 5728
   182 8097506 [sig] ssh-add 4120 pinfo::init: execed process windows pid 5892, cygwin pid 3552
   115 8097621 [sig] ssh-add 4120 pinfo::init: execed process windows pid 3104, cygwin pid 4996

This repeated many times (180 times for ssh-add.2). This occurred when I 
interrupted the processes with CTRL-C.


-- 
David Rothenberger                spammer? -> spam AT daveroth DOT dyndns DOT org
GPG/PGP: 0x7F67E734, C233 365A 25EF 2C5F C8E1 43DF B44F BA26 7F67 E734

kernel, n.:
	A part of an operating system that preserves the medieval
	traditions of sorcery and black art.





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