openssh bugs - Dec 2005 - [Bug 1135] ssh-agent auth socket problem = infinite loop 100% cpu

http://bugzilla.mindrot.org/show_bug.cgi?id=1135

           Summary: ssh-agent auth socket problem = infinite loop 100% cpu
           Product: Portable OpenSSH
           Version: 4.2p1
          Platform: All
        OS/Version: Cygwin on NT/2k
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ssh-agent
        AssignedTo: bitbucket at mindrot.org
        ReportedBy: focht at gmx.net


ssh-agent is started using .bashrc.

When i update my cygwin installation using "setup.exe" i occasionally
get the ssh-agent hanging eating 100% cpu.

Attached is a debugger session/code snippets which shows the bug

in short: select() is returning "1" while the following accept() gets
-1 (errno
= 0x6C). The main while(1) loop leads to 100% cpu usage.

No one on cygwin mailing list cared to answer so i hope someone here can shed
any lights on this.
Maybe this bug is originated within cygwin itself ...

Its very annyoing bug because i often update cygwin installations and have to
kill ssh-agent manually (while eating 100% cpu) to continue.

Regards

A. Focht




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------- Comment #1 from focht at gmx.net  2005-12-16 20:55 -------
Created an attachment (id=1044)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=1044&action=view)
debug session and source code snippets pinpointing the problem




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------- Comment #2 from dtucker at zip.com.au  2005-12-17 21:45 -------
*** Bug 1134 has been marked as a duplicate of this bug. ***




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------- Comment #3 from dtucker at zip.com.au  2005-12-17 22:37 -------
I would guess that you have problems when setup.exe updates the cygwin dll
while ssh-agent is still using it.  I have no idea what is happening under the
covers though (or even if an update while cygwin processes are still running is
even supported?)




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------- Comment #4 from focht at gmx.net  2005-12-18 06:53 -------
(In reply to comment #3)
> I would guess that you have problems when setup.exe updates the cygwin dll
> while ssh-agent is still using it.  I have no idea what is happening under
the
> covers though (or even if an update while cygwin processes are still
running is
> even supported?)
> 
Hello again,

no the cygwin dynamic library is not updated/replaced when this occurs.
I examined the setup.log.full after each install and tells like this:

--- snip ---
....
2005/12/16 23:24:59 running: e:\cygwin\bin\bash.exe -c
/etc/postinstall/update-info-dir.sh
Agent pid 3148
Could not open a connection to your authentication agent.
2005/12/16 23:25:28 abnormal exit: exit code=0
2005/12/16 23:25:34 mbox note: Installation Complete
2005/12/16 23:25:34 Ending cygwin install
...
--- snip ---

As posted before, my .bashrc contains

----- snip ----

[ -z "$SSH_AUTH_SOCK" ] && eval `ssh-agent -s`
[ -z "$SSH_AGENT_PID" ] || ssh-add -l >/dev/null 2>&1 ||
ssh-add

--- snip ---

Each time bash is started, this gets executed and the following lines appear on
my shell:

--- snip ---

Agent pid xxxx
Identity added: /home/focht/.ssh/id_rsa (/home/focht/.ssh/id_rsa)

focht at xxxx ~
$ 
--- snip ---

Maybe there is some kind of race condition somewhere because there is a line in
setup log saying "Could not open a connection to your authentication
agent."

I guess its some kind of socket problem .. 

select() = ok (returns 1)
accept() = fail (returns -1, errno: shutdown)

Regards




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