1.7.2 on 2008 SP2: man segfaults + X problems

[Mark McConnell <markd dot mcconnell at gmail dot com>]

I am running the XWin X Server
Release: 1.7.6.0 (10706000)
Build Date: 2010-03-22

After installing Cygwin 1.7.2 for the first time on Windows Server
2008 SP2, I discovered several indications of a problem with my Cygwin
installation. I describe 4 "symptoms" below.

SYMPTOM 1
 man* dumps core after a Segmentation fault

$ man man
Segmentation fault (core dumped)

================
SYMPTOM 2
 Local gvim gui does not display.  I launch gvim in one terminal, and
observe the processes in a second terminal.

pt0 $ gvim
|

The process is unresponsive to ^C or ^D, or ^Z.  It cannot be directly
killed from the other terminal.

pt1 $ ps ; $ kill 4760
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     4868       1    4868       4876  con 11137 15:30:13 /usr/bin/XWin
     2916    4868    2916       5256    ? 11137 15:32:28 /usr/bin/mintty
     5276    2916    5276       3352    0 11137 15:32:28 /usr/bin/bash
     4760    5276    4760       5024    0 11137 15:48:23 /usr/bin/gvim
bash: kill: (4760) - Resource temporarily unavailable

Closing the first terminal from which gvim was started, gvim continues
to run in the background. I kill the orphaned gvim process using
Windows Task Manager.

Other gui programs launch and close without evident problems (e.g.
xterm, wxdemo)

================
SYMPTOM 3
 I cannot connect to a remote host using Cygwin's ssh, if X is
forwarded.    "ssh -X host"  authenticates but is unresponsive
_until_ the PPID of xauth is killed.

To reproduce and observe the problem, I launch two instances of mintty
from the cygwin environment.  I will use the second instance to watch
the processes.

pt0 $ echo $DISPLAY
 :0.0

In the first shell I attempt to connect with ssh to 'host' using the
-X or -Y switch.

pt0 $ ssh -X dasftp
|

The cursor returns below the prompt.  ^D or ^C do not terminate the
process ( however, I can suspend the process from that window by
typing ^Z, and return it to the foreground with fg* ).

In the second terminal I  look at the processes running on tty0

pt1 $ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     5852       1    5852       4640  con 11137 10:26:21 /usr/bin/XWin
     4468    5852    4468        568    ? 11137 10:27:01 /usr/bin/mintty
     6032    4468    6032       1644    0 11137 10:27:02 /usr/bin/bash
     4208    6032    4208       5036    0 11137 10:47:30 /usr/bin/ssh
     3200    4208    4208       3200    0 11137 10:47:31 /usr/bin/sh
     1152    3200    4208       3048    0 11137 10:47:31 /usr/bin/xauth

I attempt to kill  xauth* from the second terminal:

pt1 $  kill 1152
bash: kill: (1152) - Resource temporarily unavailable

I kill the PPID of xauth; when /usr/bin/sh dies, the remote prompt
immediately appears in the first terminal

pt1 $ kill 3200 ; ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     5852       1    5852       4640  con 11137 10:26:21 /usr/bin/XWin
     4468    5852    4468        568    ? 11137 10:27:01 /usr/bin/mintty
I    6032    4468    6032       1644    0 11137 10:27:02 /usr/bin/bash
     1152       1    4208       3048    0 11137 10:47:31 /usr/bin/xauth

pt0 $ ssh -X dasftp
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Warning: No xauth data; using fake authentication data for X11 forwarding.
  WELCOME to dasftp
markmc@dasftp~ $ gvim
markmc@dasftp~ $           # (succeeds)

I can launch the remote gui in X

I close the remote gvim gui, logout from 'host' and exit from bash* ,
closing the first instance of mintty.  xauth* is still running with 1
as the parent.  I kill the orphaned xauth process using Windows Task
Manager.

pt1 $ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     5852       1    5852       4640  con 11137 10:26:21 /usr/bin/XWin
     1152       1    4208       3048    0 11137 10:47:31 /usr/bin/xauth

================
SYMPTOM 4
  'ssh -Y host' is unresponsive _regardless_ of whether the xauth PPID is killed

As above, the cursor returns below the prompt.  ^D or ^C do not
terminate the process ( however, I can suspend the process from that
window by typing ^Z, and return it to the foreground with fg* ).

However, using the same steps as in the SYMPTOM 3 experiment, killing
the PPID of xauth does not work the same. Although ssh has
authenticated on the remote machine, I do not receive a shell prompt.
'ssh -Y host gui' also does not display the remote gui, after killing
the parent process (in contrast to 'ssh -X host gui').

pt1 $ ps ; kill 5848 # ( /usr/bin/sh is killed with no warnings issued)
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     4868       1    4868       4876  con 11137 15:30:13 /usr/bin/XWin
     2916    4868    2916       5256    ? 11137 15:32:28 /usr/bin/mintty
I    5060    5276    5060        940    0 11137 15:37:09 /usr/bin/ssh
     5848    5060    5060       5848    0 11137 15:37:10 /usr/bin/sh
     4904    5848    5060       3232    0 11137 15:37:10 /usr/bin/xauth

ps0 $ ssh -Y dasftp gvim #( unresponsive to kill)
|

ps0 $ kill 4904  # ( xauth cannot be killed from within the Cygwin environment)
bash: kill: (4904) - Resource temporarily unavailable

 In the second terminal, I kill the ssh process:
pt1 $  kill 5060

ps0 $ ssh -Y dasftp gvim
Warning: No xauth data; using fake authentication data for X11 forwarding.
Killed by signal 15.
ps0 $

ssh sucessfully authenticated on the remote machine, but I do not
receive a shell prompt in the terminal window after killing the PPID
of xauth when I use 'ssh -Y host', and a gui does not launch over the
forwarded X; this is different behavior than 'ssh -X host' .  I kill
the orphaned xauth process using Windows Task Manager.

================
SUMMARY
It appears that something is basically wrong with my installation or
environment.  If I'm really lucky, maybe I've described four points of
view over the same problem!   I was directed to this group after
describing my X problems on cygwin-xfree.

The behaviors I've described were observed in Cygwin installed under a
privileged user, but were identical after a complete re-install as the
local Administrator.  The Win32 Server 2008 installation is running
with Terminal Server, IIS and File Services roles enabled.  It is a
fresh install, with most components still set according to their
defaults (Cygwin was one of the first third-party components that I
attempted to install).

 I'm attaching XWin.0.log, and the output of 'cygcheck -s -v -r', as
well as the debug output of 'ssh -v -v -X host'.

Many Thanks,
Mark
--

Attachment: cygcheck_out.txt
Description: Text document

Attachment: ssh_out.txt
Description: Text document

Attachment: XWin.0.log.txt
Description: Text document

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